diff --git a/libs/spandsp/spandsp-sim/make_line_models.c b/libs/spandsp/spandsp-sim/make_line_models.c
index fd7b81f72f..300de80c22 100644
--- a/libs/spandsp/spandsp-sim/make_line_models.c
+++ b/libs/spandsp/spandsp-sim/make_line_models.c
@@ -787,7 +787,7 @@ static void generate_ad_edd(void)
     float offset;
     float amp;
     float phase;
-    float delay;
+    //float delay;
     float pw;
 #if defined(HAVE_FFTW3_H)
     double in[FFT_SIZE][2];
@@ -836,7 +836,7 @@ static void generate_ad_edd(void)
                     amp = (1.0 - offset)*ad[l - 1].ad[j] + offset*ad[l].ad[j];
                     amp = pow(10.0, -amp/20.0);
                 }
-                delay = 0.0f;
+                //delay = 0.0f;
                 for (l = 0;  l < (int) (sizeof(edd)/sizeof(edd[0]));  l++)
                 {
                     if (f < edd[l].freq)
@@ -845,7 +845,7 @@ static void generate_ad_edd(void)
                 if (l < (int) (sizeof(edd)/sizeof(edd[0])))
                 {
                     offset = (f - edd[l - 1].freq)/(edd[l].freq - edd[l - 1].freq);
-                    delay = (1.0f - offset)*edd[l - 1].edd[k] + offset*edd[l].edd[k];
+                    //delay = (1.0f - offset)*edd[l - 1].edd[k] + offset*edd[l].edd[k];
                 }
                 //phase = 2.0f*M_PI*f*delay*0.001f;
                 phase = 0.0f;
@@ -915,7 +915,7 @@ static void generate_proakis(void)
     float offset;
     float amp;
     float phase;
-    float delay;
+    //float delay;
     float pw;
     int index;
     int i;
@@ -953,7 +953,7 @@ static void generate_proakis(void)
 
         /* Linear interpolation */
         amp = ((1.0f - offset)*proakis[index].amp + offset*proakis[index + 1].amp)/2.3f;
-        delay = (1.0f - offset)*proakis[index].delay + offset*proakis[index + 1].delay;
+        //delay = (1.0f - offset)*proakis[index].delay + offset*proakis[index + 1].delay;
         //phase = 2.0f*M_PI*f*delay*0.001f;
         phase = 0.0f;
 #if defined(HAVE_FFTW3_H)
diff --git a/libs/spandsp/src/at_interpreter.c b/libs/spandsp/src/at_interpreter.c
index 73625ef8d7..ba29e55469 100644
--- a/libs/spandsp/src/at_interpreter.c
+++ b/libs/spandsp/src/at_interpreter.c
@@ -5501,9 +5501,9 @@ SPAN_DECLARE(void) at_set_class1_handler(at_state_t *s, at_class1_handler_t hand
 /*- End of function --------------------------------------------------------*/
 
 SPAN_DECLARE(at_state_t *) at_init(at_state_t *s,
-                                   at_tx_handler_t *at_tx_handler,
+                                   at_tx_handler_t at_tx_handler,
                                    void *at_tx_user_data,
-                                   at_modem_control_handler_t *modem_control_handler,
+                                   at_modem_control_handler_t modem_control_handler,
                                    void *modem_control_user_data)
 {
     if (s == NULL)
diff --git a/libs/spandsp/src/fax.c b/libs/spandsp/src/fax.c
index c5422e7a52..ce28fde882 100644
--- a/libs/spandsp/src/fax.c
+++ b/libs/spandsp/src/fax.c
@@ -173,8 +173,8 @@ static void hdlc_underflow_handler(void *user_data)
 /*- End of function --------------------------------------------------------*/
 
 static void set_rx_handler(fax_state_t *s,
-                           span_rx_handler_t *rx_handler,
-                           span_rx_fillin_handler_t *fillin_handler,
+                           span_rx_handler_t rx_handler,
+                           span_rx_fillin_handler_t fillin_handler,
                            void *user_data)
 {
     s->modems.rx_handler = rx_handler;
@@ -183,14 +183,14 @@ static void set_rx_handler(fax_state_t *s,
 }
 /*- End of function --------------------------------------------------------*/
 
-static void fax_modems_set_tx_handler(fax_state_t *s, span_tx_handler_t *handler, void *user_data)
+static void fax_modems_set_tx_handler(fax_state_t *s, span_tx_handler_t handler, void *user_data)
 {
     s->modems.tx_handler = handler;
     s->modems.tx_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-static void fax_modems_set_next_tx_handler(fax_state_t *s, span_tx_handler_t *handler, void *user_data)
+static void fax_modems_set_next_tx_handler(fax_state_t *s, span_tx_handler_t handler, void *user_data)
 {
     s->modems.next_tx_handler = handler;
     s->modems.next_tx_user_data = user_data;
@@ -209,7 +209,7 @@ static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
     {
         /* The fast modem has trained, so we no longer need to run the slow one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.17 (%.2fdBm0)\n", v17_rx_signal_power(&s->fast_modems.v17_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v17_rx, (span_rx_fillin_handler_t *) &v17_rx_fillin, &s->fast_modems.v17_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v17_rx, (span_rx_fillin_handler_t) &v17_rx_fillin, &s->fast_modems.v17_rx);
     }
     else
     {
@@ -219,7 +219,7 @@ static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
             /* We have received something, and the fast modem has not trained. We must
                be receiving valid V.21 */
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
     }
     return 0;
@@ -251,7 +251,7 @@ static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
     {
         /* The fast modem has trained, so we no longer need to run the slow one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.27ter (%.2fdBm0)\n", v27ter_rx_signal_power(&s->fast_modems.v27ter_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v27ter_rx, (span_rx_fillin_handler_t *) &v27ter_rx_fillin, &s->fast_modems.v27ter_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v27ter_rx, (span_rx_fillin_handler_t) &v27ter_rx_fillin, &s->fast_modems.v27ter_rx);
     }
     else
     {
@@ -261,7 +261,7 @@ static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
             /* We have received something, and the fast modem has not trained. We must
                be receiving valid V.21 */
             span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
     }
     return 0;
@@ -293,7 +293,7 @@ static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
     {
         /* The fast modem has trained, so we no longer need to run the slow one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&s->fast_modems.v29_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v29_rx, (span_rx_fillin_handler_t *) &v29_rx_fillin, &s->fast_modems.v29_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v29_rx, (span_rx_fillin_handler_t) &v29_rx_fillin, &s->fast_modems.v29_rx);
     }
     else
     {
@@ -303,7 +303,7 @@ static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
             /* We have received something, and the fast modem has not trained. We must
                be receiving valid V.21 */
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
     }
     return 0;
@@ -380,8 +380,8 @@ static int set_next_tx_type(fax_state_t *s)
     }
     /* If there is nothing else to change to, so use zero length silence */
     silence_gen_alter(&t->silence_gen, 0);
-    fax_modems_set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-    fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+    fax_modems_set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+    fax_modems_set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
     t->transmit = FALSE;
     return -1;
 }
@@ -466,7 +466,7 @@ static void fax_set_rx_type(void *user_data, int type, int bit_rate, int short_t
     case T30_MODEM_V21:
         fsk_rx_init(&t->v21_rx, &preset_fsk_specs[FSK_V21CH2], FSK_FRAME_MODE_SYNC, (put_bit_func_t) hdlc_rx_put_bit, put_bit_user_data);
         fsk_rx_signal_cutoff(&t->v21_rx, -45.5f);
-        set_rx_handler(s, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &t->v21_rx);
+        set_rx_handler(s, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &t->v21_rx);
         break;
     case T30_MODEM_V27TER:
         v27ter_rx_restart(&t->fast_modems.v27ter_rx, bit_rate, FALSE);
@@ -486,7 +486,7 @@ static void fax_set_rx_type(void *user_data, int type, int bit_rate, int short_t
     case T30_MODEM_DONE:
         span_log(&s->logging, SPAN_LOG_FLOW, "FAX exchange complete\n");
     default:
-        set_rx_handler(s, (span_rx_handler_t *) &span_dummy_rx, (span_rx_fillin_handler_t *) &span_dummy_rx_fillin, s);
+        set_rx_handler(s, (span_rx_handler_t) &span_dummy_rx, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, s);
         break;
     }
 }
@@ -519,8 +519,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
     {
     case T30_MODEM_PAUSE:
         silence_gen_alter(&t->silence_gen, ms_to_samples(short_train));
-        fax_modems_set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         t->transmit = TRUE;
         break;
     case T30_MODEM_CED:
@@ -530,8 +530,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
         else
             tone = MODEM_CONNECT_TONES_FAX_CNG;
         modem_connect_tones_tx_init(&t->connect_tx, tone);
-        fax_modems_set_tx_handler(s, (span_tx_handler_t *) &modem_connect_tones_tx, &t->connect_tx);
-        fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         t->transmit = TRUE;
         break;
     case T30_MODEM_V21:
@@ -543,8 +543,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
            a 75ms gap before any V.21 transmission is harmless, adds little to the overall length of
            a call, and ensures the receiving end is ready. */
         silence_gen_alter(&t->silence_gen, ms_to_samples(75));
-        fax_modems_set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) &fsk_tx, &t->v21_tx);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) &fsk_tx, &t->v21_tx);
         t->transmit = TRUE;
         break;
     case T30_MODEM_V27TER:
@@ -553,8 +553,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
         hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
         v27ter_tx_restart(&t->fast_modems.v27ter_tx, bit_rate, t->use_tep);
         v27ter_tx_set_get_bit(&t->fast_modems.v27ter_tx, get_bit_func, get_bit_user_data);
-        fax_modems_set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) &v27ter_tx, &t->fast_modems.v27ter_tx);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) &v27ter_tx, &t->fast_modems.v27ter_tx);
         t->transmit = TRUE;
         break;
     case T30_MODEM_V29:
@@ -563,8 +563,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
         hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
         v29_tx_restart(&t->fast_modems.v29_tx, bit_rate, t->use_tep);
         v29_tx_set_get_bit(&t->fast_modems.v29_tx, get_bit_func, get_bit_user_data);
-        fax_modems_set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) &v29_tx, &t->fast_modems.v29_tx);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) &v29_tx, &t->fast_modems.v29_tx);
         t->transmit = TRUE;
         break;
     case T30_MODEM_V17:
@@ -573,8 +573,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
         hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
         v17_tx_restart(&t->fast_modems.v17_tx, bit_rate, t->use_tep, short_train);
         v17_tx_set_get_bit(&t->fast_modems.v17_tx, get_bit_func, get_bit_user_data);
-        fax_modems_set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) &v17_tx, &t->fast_modems.v17_tx);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) &v17_tx, &t->fast_modems.v17_tx);
         t->transmit = TRUE;
         break;
     case T30_MODEM_DONE:
@@ -582,8 +582,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
         /* Fall through */
     default:
         silence_gen_alter(&t->silence_gen, 0);
-        fax_modems_set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        fax_modems_set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         t->transmit = FALSE;
         break;
     }
diff --git a/libs/spandsp/src/fax_modems.c b/libs/spandsp/src/fax_modems.c
index cad8594592..d684f03d54 100644
--- a/libs/spandsp/src/fax_modems.c
+++ b/libs/spandsp/src/fax_modems.c
@@ -98,8 +98,8 @@ SPAN_DECLARE_NONSTD(int) fax_modems_v17_v21_rx(void *user_data, const int16_t am
         /* We have received something, and the fast modem has not trained. We must
            be receiving valid V.21 */
         span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-        s->rx_handler = (span_rx_handler_t *) &fsk_rx;
-        s->rx_fillin_handler = (span_rx_fillin_handler_t *) &fsk_rx_fillin;
+        s->rx_handler = (span_rx_handler_t) &fsk_rx;
+        s->rx_fillin_handler = (span_rx_fillin_handler_t) &fsk_rx_fillin;
         s->rx_user_data = &s->v21_rx;
     }
     return 0;
@@ -129,8 +129,8 @@ SPAN_DECLARE_NONSTD(int) fax_modems_v27ter_v21_rx(void *user_data, const int16_t
         /* We have received something, and the fast modem has not trained. We must
            be receiving valid V.21 */
         span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-        s->rx_handler = (span_rx_handler_t *) &fsk_rx;
-        s->rx_fillin_handler = (span_rx_fillin_handler_t *) &fsk_rx_fillin;
+        s->rx_handler = (span_rx_handler_t) &fsk_rx;
+        s->rx_fillin_handler = (span_rx_fillin_handler_t) &fsk_rx_fillin;
         s->rx_user_data = &s->v21_rx;
     }
     return 0;
@@ -160,8 +160,8 @@ SPAN_DECLARE_NONSTD(int) fax_modems_v29_v21_rx(void *user_data, const int16_t am
         /* We have received something, and the fast modem has not trained. We must
            be receiving valid V.21 */
         span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-        s->rx_handler = (span_rx_handler_t *) &fsk_rx;
-        s->rx_fillin_handler = (span_rx_fillin_handler_t *) &fsk_rx_fillin;
+        s->rx_handler = (span_rx_handler_t) &fsk_rx;
+        s->rx_fillin_handler = (span_rx_fillin_handler_t) &fsk_rx_fillin;
         s->rx_user_data = &s->v21_rx;
     }
     return 0;
@@ -181,9 +181,11 @@ SPAN_DECLARE_NONSTD(int) fax_modems_v29_v21_rx_fillin(void *user_data, int len)
 
 static void v21_rx_status_handler(void *user_data, int status)
 {
+#if 0
     fax_modems_state_t *s;
 
     s = (fax_modems_state_t *) user_data;
+#endif
 }
 /*- End of function --------------------------------------------------------*/
 
@@ -196,8 +198,8 @@ static void v17_rx_status_handler(void *user_data, int status)
     {
     case SIG_STATUS_TRAINING_SUCCEEDED:
         span_log(&s->logging, SPAN_LOG_FLOW, "Switching to V.17 (%.2fdBm0)\n", v17_rx_signal_power(&s->fast_modems.v17_rx));
-        s->rx_handler = (span_rx_handler_t *) &v17_rx;
-        s->rx_fillin_handler = (span_rx_fillin_handler_t *) &v17_rx_fillin;
+        s->rx_handler = (span_rx_handler_t) &v17_rx;
+        s->rx_fillin_handler = (span_rx_fillin_handler_t) &v17_rx_fillin;
         s->rx_user_data = &s->fast_modems.v17_rx;
         break;
     }
@@ -213,8 +215,8 @@ static void v27ter_rx_status_handler(void *user_data, int status)
     {
     case SIG_STATUS_TRAINING_SUCCEEDED:
         span_log(&s->logging, SPAN_LOG_FLOW, "Switching to V.27ter (%.2fdBm0)\n", v27ter_rx_signal_power(&s->fast_modems.v27ter_rx));
-        s->rx_handler = (span_rx_handler_t *) &v27ter_rx;
-        s->rx_fillin_handler = (span_rx_fillin_handler_t *) &v27ter_rx_fillin;
+        s->rx_handler = (span_rx_handler_t) &v27ter_rx;
+        s->rx_fillin_handler = (span_rx_fillin_handler_t) &v27ter_rx_fillin;
         s->rx_user_data = &s->fast_modems.v27ter_rx;
         break;
     }
@@ -230,8 +232,8 @@ static void v29_rx_status_handler(void *user_data, int status)
     {
     case SIG_STATUS_TRAINING_SUCCEEDED:
         span_log(&s->logging, SPAN_LOG_FLOW, "Switching to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&s->fast_modems.v29_rx));
-        s->rx_handler = (span_rx_handler_t *) &v29_rx;
-        s->rx_fillin_handler = (span_rx_fillin_handler_t *) &v29_rx_fillin;
+        s->rx_handler = (span_rx_handler_t) &v29_rx;
+        s->rx_fillin_handler = (span_rx_fillin_handler_t) &v29_rx_fillin;
         s->rx_user_data = &s->fast_modems.v29_rx;
         break;
     }
@@ -315,10 +317,10 @@ SPAN_DECLARE(fax_modems_state_t *) fax_modems_init(fax_modems_state_t *s,
     dc_restore_init(&s->dc_restore);
 
     s->rx_signal_present = FALSE;
-    s->rx_handler = (span_rx_handler_t *) &span_dummy_rx;
-    s->rx_fillin_handler = (span_rx_fillin_handler_t *) &span_dummy_rx;
+    s->rx_handler = (span_rx_handler_t) &span_dummy_rx;
+    s->rx_fillin_handler = (span_rx_fillin_handler_t) &span_dummy_rx;
     s->rx_user_data = NULL;
-    s->tx_handler = (span_tx_handler_t *) &silence_gen;
+    s->tx_handler = (span_tx_handler_t) &silence_gen;
     s->tx_user_data = &s->silence_gen;
     return s;
 }
diff --git a/libs/spandsp/src/spandsp/at_interpreter.h b/libs/spandsp/src/spandsp/at_interpreter.h
index 6f844599f0..d4c8f0018e 100644
--- a/libs/spandsp/src/spandsp/at_interpreter.h
+++ b/libs/spandsp/src/spandsp/at_interpreter.h
@@ -38,9 +38,9 @@ modem control commands.
 
 typedef struct at_state_s at_state_t;
 
-typedef int (at_modem_control_handler_t)(at_state_t *s, void *user_data, int op, const char *num);
-typedef int (at_tx_handler_t)(at_state_t *s, void *user_data, const uint8_t *buf, size_t len);
-typedef int (at_class1_handler_t)(at_state_t *s, void *user_data, int direction, int operation, int val);
+typedef int (*at_modem_control_handler_t)(at_state_t *s, void *user_data, int op, const char *num);
+typedef int (*at_tx_handler_t)(at_state_t *s, void *user_data, const uint8_t *buf, size_t len);
+typedef int (*at_class1_handler_t)(at_state_t *s, void *user_data, int direction, int operation, int val);
 
 enum at_rx_mode_e
 {
@@ -172,9 +172,9 @@ SPAN_DECLARE(void) at_set_class1_handler(at_state_t *s, at_class1_handler_t hand
     \param modem_control_user_data x.
     \return A pointer to the AT context, or NULL if there was a problem. */
 SPAN_DECLARE(at_state_t *) at_init(at_state_t *s,
-                                   at_tx_handler_t *at_tx_handler,
+                                   at_tx_handler_t at_tx_handler,
                                    void *at_tx_user_data,
-                                   at_modem_control_handler_t *modem_control_handler,
+                                   at_modem_control_handler_t modem_control_handler,
                                    void *modem_control_user_data);
 
 /*! Release an AT interpreter context.
diff --git a/libs/spandsp/src/spandsp/private/at_interpreter.h b/libs/spandsp/src/spandsp/private/at_interpreter.h
index da13b5a2bb..a99dea9a35 100644
--- a/libs/spandsp/src/spandsp/private/at_interpreter.h
+++ b/libs/spandsp/src/spandsp/private/at_interpreter.h
@@ -113,11 +113,11 @@ struct at_state_s
     char line[256];
     int line_ptr;
 
-    at_modem_control_handler_t *modem_control_handler;
+    at_modem_control_handler_t modem_control_handler;
     void *modem_control_user_data;
-    at_tx_handler_t *at_tx_handler;
+    at_tx_handler_t at_tx_handler;
     void *at_tx_user_data;
-    at_class1_handler_t *class1_handler;
+    at_class1_handler_t class1_handler;
     void *class1_user_data;
 
     /*! \brief Error and flow logging control */
diff --git a/libs/spandsp/src/spandsp/private/fax_modems.h b/libs/spandsp/src/spandsp/private/fax_modems.h
index 4250198ded..f45969bb94 100644
--- a/libs/spandsp/src/spandsp/private/fax_modems.h
+++ b/libs/spandsp/src/spandsp/private/fax_modems.h
@@ -95,18 +95,18 @@ struct fax_modems_state_s
     int rx_frame_received;
 
     /*! \brief The current receive signal handler */
-    span_rx_handler_t *rx_handler;
+    span_rx_handler_t rx_handler;
     /*! \brief The current receive missing signal fill-in handler */
-    span_rx_fillin_handler_t *rx_fillin_handler;
+    span_rx_fillin_handler_t rx_fillin_handler;
     void *rx_user_data;
 
     /*! \brief The current transmit signal handler */
-    span_tx_handler_t *tx_handler;
+    span_tx_handler_t tx_handler;
     void *tx_user_data;
 
     /*! The next transmit signal handler, for two stage transmit operations.
         E.g. a short silence followed by a modem signal. */
-    span_tx_handler_t *next_tx_handler;
+    span_tx_handler_t next_tx_handler;
     void *next_tx_user_data;
 
     /*! The current bit rate of the transmitter. */
diff --git a/libs/spandsp/src/spandsp/private/t30.h b/libs/spandsp/src/spandsp/private/t30.h
index 8cd890b9e0..a8f23c0197 100644
--- a/libs/spandsp/src/spandsp/private/t30.h
+++ b/libs/spandsp/src/spandsp/private/t30.h
@@ -94,42 +94,42 @@ struct t30_state_s
 
     /*! \brief A pointer to a callback routine to be called when phase B events
         occur. */
-    t30_phase_b_handler_t *phase_b_handler;
+    t30_phase_b_handler_t phase_b_handler;
     /*! \brief An opaque pointer supplied in event B callbacks. */
     void *phase_b_user_data;
     /*! \brief A pointer to a callback routine to be called when phase D events
         occur. */
-    t30_phase_d_handler_t *phase_d_handler;
+    t30_phase_d_handler_t phase_d_handler;
     /*! \brief An opaque pointer supplied in event D callbacks. */
     void *phase_d_user_data;
     /*! \brief A pointer to a callback routine to be called when phase E events
         occur. */
-    t30_phase_e_handler_t *phase_e_handler;
+    t30_phase_e_handler_t phase_e_handler;
     /*! \brief An opaque pointer supplied in event E callbacks. */
     void *phase_e_user_data;
     /*! \brief A pointer to a callback routine to be called when frames are
         exchanged. */
-    t30_real_time_frame_handler_t *real_time_frame_handler;
+    t30_real_time_frame_handler_t real_time_frame_handler;
     /*! \brief An opaque pointer supplied in real time frame callbacks. */
     void *real_time_frame_user_data;
 
     /*! \brief A pointer to a callback routine to be called when document events
         (e.g. end of transmitted document) occur. */
-    t30_document_handler_t *document_handler;
+    t30_document_handler_t document_handler;
     /*! \brief An opaque pointer supplied in document callbacks. */
     void *document_user_data;
 
     /*! \brief The handler for changes to the receive mode */
-    t30_set_handler_t *set_rx_type_handler;
+    t30_set_handler_t set_rx_type_handler;
     /*! \brief An opaque pointer passed to the handler for changes to the receive mode */
     void *set_rx_type_user_data;
     /*! \brief The handler for changes to the transmit mode */
-    t30_set_handler_t *set_tx_type_handler;
+    t30_set_handler_t set_tx_type_handler;
     /*! \brief An opaque pointer passed to the handler for changes to the transmit mode */
     void *set_tx_type_user_data;
 
     /*! \brief The transmitted HDLC frame handler. */
-    t30_send_hdlc_handler_t *send_hdlc_handler;
+    t30_send_hdlc_handler_t send_hdlc_handler;
     /*! \brief An opaque pointer passed to the transmitted HDLC frame handler. */
     void *send_hdlc_user_data;
 
diff --git a/libs/spandsp/src/spandsp/private/t31.h b/libs/spandsp/src/spandsp/private/t31.h
index ee481c5151..fafdf72341 100644
--- a/libs/spandsp/src/spandsp/private/t31.h
+++ b/libs/spandsp/src/spandsp/private/t31.h
@@ -36,7 +36,7 @@ typedef struct
     v8_state_t v8;
 
     /*! The transmit signal handler to be used when the current one has finished sending. */
-    span_tx_handler_t *next_tx_handler;
+    span_tx_handler_t next_tx_handler;
     void *next_tx_user_data;
 
     /*! \brief No of data bits in current_byte. */
@@ -136,7 +136,7 @@ typedef struct
 struct t31_state_s
 {
     at_state_t at_state;
-    t31_modem_control_handler_t *modem_control_handler;
+    t31_modem_control_handler_t modem_control_handler;
     void *modem_control_user_data;
 
     t31_audio_front_end_state_t audio;
diff --git a/libs/spandsp/src/spandsp/private/t38_core.h b/libs/spandsp/src/spandsp/private/t38_core.h
index de0aac9d60..e965ca6f40 100644
--- a/libs/spandsp/src/spandsp/private/t38_core.h
+++ b/libs/spandsp/src/spandsp/private/t38_core.h
@@ -32,16 +32,16 @@
 struct t38_core_state_s
 {
     /*! \brief Handler routine to transmit IFP packets generated by the T.38 protocol engine */
-    t38_tx_packet_handler_t *tx_packet_handler;
+    t38_tx_packet_handler_t tx_packet_handler;
     /*! \brief An opaque pointer passed to tx_packet_handler */
     void *tx_packet_user_data;
 
     /*! \brief Handler routine to process received indicator packets */
-    t38_rx_indicator_handler_t *rx_indicator_handler;
+    t38_rx_indicator_handler_t rx_indicator_handler;
     /*! \brief Handler routine to process received data packets */
-    t38_rx_data_handler_t *rx_data_handler;
+    t38_rx_data_handler_t rx_data_handler;
     /*! \brief Handler routine to process the missing packet condition */
-    t38_rx_missing_handler_t *rx_missing_handler;
+    t38_rx_missing_handler_t rx_missing_handler;
     /*! \brief An opaque pointer passed to any of the above receive handling routines */
     void *rx_user_data;
 
diff --git a/libs/spandsp/src/spandsp/private/t38_gateway.h b/libs/spandsp/src/spandsp/private/t38_gateway.h
index 54a935a270..d7cd549264 100644
--- a/libs/spandsp/src/spandsp/private/t38_gateway.h
+++ b/libs/spandsp/src/spandsp/private/t38_gateway.h
@@ -61,8 +61,8 @@ typedef struct
     fax_modems_state_t modems;
     /*! \brief The current receive signal handler. Actual receiving hops between this
                and a dummy receive routine. */
-    span_rx_handler_t *base_rx_handler;
-    span_rx_fillin_handler_t *base_rx_fillin_handler;
+    span_rx_handler_t base_rx_handler;
+    span_rx_fillin_handler_t base_rx_fillin_handler;
 } t38_gateway_audio_state_t;
 
 /*!
@@ -183,7 +183,7 @@ typedef struct
 
     /*! \brief A pointer to a callback routine to be called when frames are
         exchanged. */
-    t38_gateway_real_time_frame_handler_t *real_time_frame_handler;
+    t38_gateway_real_time_frame_handler_t real_time_frame_handler;
     /*! \brief An opaque pointer supplied in real time frame callbacks. */
     void *real_time_frame_user_data;
 } t38_gateway_core_state_t;
diff --git a/libs/spandsp/src/spandsp/private/v8.h b/libs/spandsp/src/spandsp/private/v8.h
index 2fb481d0b2..77dd55eea0 100644
--- a/libs/spandsp/src/spandsp/private/v8.h
+++ b/libs/spandsp/src/spandsp/private/v8.h
@@ -32,7 +32,7 @@ struct v8_state_s
     int calling_party;
 
     /*! \brief A handler to process the V.8 signals */
-    v8_result_handler_t *result_handler;
+    v8_result_handler_t result_handler;
     /*! \brief An opaque pointer passed to result_handler */
     void *result_handler_user_data;
 
diff --git a/libs/spandsp/src/spandsp/t30.h b/libs/spandsp/src/spandsp/t30.h
index 2f97729859..8c0edffd83 100644
--- a/libs/spandsp/src/spandsp/t30.h
+++ b/libs/spandsp/src/spandsp/t30.h
@@ -158,7 +158,7 @@ typedef struct t30_state_s t30_state_t;
     \param result The phase B event code.
     \return The new status. Normally, T30_ERR_OK is returned.
 */
-typedef int (t30_phase_b_handler_t)(t30_state_t *s, void *user_data, int result);
+typedef int (*t30_phase_b_handler_t)(t30_state_t *s, void *user_data, int result);
 
 /*!
     T.30 phase D callback handler.
@@ -168,7 +168,7 @@ typedef int (t30_phase_b_handler_t)(t30_state_t *s, void *user_data, int result)
     \param result The phase D event code.
     \return The new status. Normally, T30_ERR_OK is returned.
 */
-typedef int (t30_phase_d_handler_t)(t30_state_t *s, void *user_data, int result);
+typedef int (*t30_phase_d_handler_t)(t30_state_t *s, void *user_data, int result);
 
 /*!
     T.30 phase E callback handler.
@@ -177,7 +177,7 @@ typedef int (t30_phase_d_handler_t)(t30_state_t *s, void *user_data, int result)
     \param user_data An opaque pointer.
     \param completion_code The phase E completion code.
 */
-typedef void (t30_phase_e_handler_t)(t30_state_t *s, void *user_data, int completion_code);
+typedef void (*t30_phase_e_handler_t)(t30_state_t *s, void *user_data, int completion_code);
 
 /*!
     T.30 real time frame handler.
@@ -188,11 +188,11 @@ typedef void (t30_phase_e_handler_t)(t30_state_t *s, void *user_data, int comple
     \param msg The HDLC message.
     \param len The length of the message.
 */
-typedef void (t30_real_time_frame_handler_t)(t30_state_t *s,
-                                             void *user_data,
-                                             int direction,
-                                             const uint8_t msg[],
-                                             int len);
+typedef void (*t30_real_time_frame_handler_t)(t30_state_t *s,
+                                              void *user_data,
+                                              int direction,
+                                              const uint8_t msg[],
+                                              int len);
 
 /*!
     T.30 document handler.
@@ -201,7 +201,7 @@ typedef void (t30_real_time_frame_handler_t)(t30_state_t *s,
     \param user_data An opaque pointer.
     \param result The document event code.
 */
-typedef int (t30_document_handler_t)(t30_state_t *s, void *user_data, int status);
+typedef int (*t30_document_handler_t)(t30_state_t *s, void *user_data, int status);
 
 /*!
     T.30 set a receive or transmit type handler.
@@ -212,7 +212,7 @@ typedef int (t30_document_handler_t)(t30_state_t *s, void *user_data, int status
     \param short_train TRUE if the short training sequence should be used (where one exists).
     \param use_hdlc FALSE for bit stream, TRUE for HDLC framing.
 */
-typedef void (t30_set_handler_t)(void *user_data, int type, int bit_rate, int short_train, int use_hdlc);
+typedef void (*t30_set_handler_t)(void *user_data, int type, int bit_rate, int short_train, int use_hdlc);
 
 /*!
     T.30 send HDLC handler.
@@ -221,7 +221,7 @@ typedef void (t30_set_handler_t)(void *user_data, int type, int bit_rate, int sh
     \param msg The HDLC message.
     \param len The length of the message.
 */
-typedef void (t30_send_hdlc_handler_t)(void *user_data, const uint8_t msg[], int len);
+typedef void (*t30_send_hdlc_handler_t)(void *user_data, const uint8_t msg[], int len);
 
 /*!
     T.30 protocol completion codes, at phase E.
@@ -572,11 +572,11 @@ extern "C"
     \return A pointer to the context, or NULL if there was a problem. */
 SPAN_DECLARE(t30_state_t *) t30_init(t30_state_t *s,
                                      int calling_party,
-                                     t30_set_handler_t *set_rx_type_handler,
+                                     t30_set_handler_t set_rx_type_handler,
                                      void *set_rx_type_user_data,
-                                     t30_set_handler_t *set_tx_type_handler,
+                                     t30_set_handler_t set_tx_type_handler,
                                      void *set_tx_type_user_data,
-                                     t30_send_hdlc_handler_t *send_hdlc_handler,
+                                     t30_send_hdlc_handler_t send_hdlc_handler,
                                      void *send_hdlc_user_data);
 
 /*! Release a T.30 context.
diff --git a/libs/spandsp/src/spandsp/t30_api.h b/libs/spandsp/src/spandsp/t30_api.h
index d758c8e871..08a0383634 100644
--- a/libs/spandsp/src/spandsp/t30_api.h
+++ b/libs/spandsp/src/spandsp/t30_api.h
@@ -507,28 +507,28 @@ SPAN_DECLARE(int) t30_set_receiver_not_ready(t30_state_t *s, int count);
     \param s The T.30 context.
     \param handler The callback function.
     \param user_data An opaque pointer passed to the callback function. */
-SPAN_DECLARE(void) t30_set_phase_b_handler(t30_state_t *s, t30_phase_b_handler_t *handler, void *user_data);
+SPAN_DECLARE(void) t30_set_phase_b_handler(t30_state_t *s, t30_phase_b_handler_t handler, void *user_data);
 
 /*! Set a callback function for T.30 phase D handling.
     \brief Set a callback function for T.30 phase D handling.
     \param s The T.30 context.
     \param handler The callback function.
     \param user_data An opaque pointer passed to the callback function. */
-SPAN_DECLARE(void) t30_set_phase_d_handler(t30_state_t *s, t30_phase_d_handler_t *handler, void *user_data);
+SPAN_DECLARE(void) t30_set_phase_d_handler(t30_state_t *s, t30_phase_d_handler_t handler, void *user_data);
 
 /*! Set a callback function for T.30 phase E handling.
     \brief Set a callback function for T.30 phase E handling.
     \param s The T.30 context.
     \param handler The callback function.
     \param user_data An opaque pointer passed to the callback function. */
-SPAN_DECLARE(void) t30_set_phase_e_handler(t30_state_t *s, t30_phase_e_handler_t *handler, void *user_data);
+SPAN_DECLARE(void) t30_set_phase_e_handler(t30_state_t *s, t30_phase_e_handler_t handler, void *user_data);
 
 /*! Set a callback function for T.30 end of document handling.
     \brief Set a callback function for T.30 end of document handling.
     \param s The T.30 context.
     \param handler The callback function.
     \param user_data An opaque pointer passed to the callback function. */
-SPAN_DECLARE(void) t30_set_document_handler(t30_state_t *s, t30_document_handler_t *handler, void *user_data);
+SPAN_DECLARE(void) t30_set_document_handler(t30_state_t *s, t30_document_handler_t handler, void *user_data);
 
 /*! Set a callback function for T.30 frame exchange monitoring. This is called from the heart
     of the signal processing, so don't take too long in the handler routine.
@@ -536,7 +536,7 @@ SPAN_DECLARE(void) t30_set_document_handler(t30_state_t *s, t30_document_handler
     \param s The T.30 context.
     \param handler The callback function.
     \param user_data An opaque pointer passed to the callback function. */
-SPAN_DECLARE(void) t30_set_real_time_frame_handler(t30_state_t *s, t30_real_time_frame_handler_t *handler, void *user_data);
+SPAN_DECLARE(void) t30_set_real_time_frame_handler(t30_state_t *s, t30_real_time_frame_handler_t handler, void *user_data);
 
 /*! Get a pointer to the logging context associated with a T.30 context.
     \brief Get a pointer to the logging context associated with a T.30 context.
diff --git a/libs/spandsp/src/spandsp/t31.h b/libs/spandsp/src/spandsp/t31.h
index 25f826d42c..80a676b207 100644
--- a/libs/spandsp/src/spandsp/t31.h
+++ b/libs/spandsp/src/spandsp/t31.h
@@ -42,7 +42,7 @@ modems in spandsp.
 */
 typedef struct t31_state_s t31_state_t;
 
-typedef int (t31_modem_control_handler_t)(t31_state_t *s, void *user_data, int op, const char *num);
+typedef int (*t31_modem_control_handler_t)(t31_state_t *s, void *user_data, int op, const char *num);
 
 #define T31_TX_BUF_LEN          (4096)
 #define T31_TX_BUF_HIGH_TIDE    (4096 - 1024)
@@ -133,11 +133,11 @@ SPAN_DECLARE(t38_core_state_t *) t31_get_t38_core_state(t31_state_t *s);
     \param tx_t38_packet_user_data ???
     \return A pointer to the T.31 context. */
 SPAN_DECLARE(t31_state_t *) t31_init(t31_state_t *s,
-                                     at_tx_handler_t *at_tx_handler,
+                                     at_tx_handler_t at_tx_handler,
                                      void *at_tx_user_data,
-                                     t31_modem_control_handler_t *modem_control_handler,
+                                     t31_modem_control_handler_t modem_control_handler,
                                      void *modem_control_user_data,
-                                     t38_tx_packet_handler_t *tx_t38_packet_handler,
+                                     t38_tx_packet_handler_t tx_t38_packet_handler,
                                      void *tx_t38_packet_user_data);
 
 /*! Release a T.31 context.
diff --git a/libs/spandsp/src/spandsp/t38_core.h b/libs/spandsp/src/spandsp/t38_core.h
index cda7a19b52..662cf8d37e 100644
--- a/libs/spandsp/src/spandsp/t38_core.h
+++ b/libs/spandsp/src/spandsp/t38_core.h
@@ -201,11 +201,11 @@ typedef struct
 */
 typedef struct t38_core_state_s t38_core_state_t;
 
-typedef int (t38_tx_packet_handler_t)(t38_core_state_t *s, void *user_data, const uint8_t *buf, int len, int count);
+typedef int (*t38_tx_packet_handler_t)(t38_core_state_t *s, void *user_data, const uint8_t *buf, int len, int count);
 
-typedef int (t38_rx_indicator_handler_t)(t38_core_state_t *s, void *user_data, int indicator);
-typedef int (t38_rx_data_handler_t)(t38_core_state_t *s, void *user_data, int data_type, int field_type, const uint8_t *buf, int len);
-typedef int (t38_rx_missing_handler_t)(t38_core_state_t *s, void *user_data, int rx_seq_no, int expected_seq_no);
+typedef int (*t38_rx_indicator_handler_t)(t38_core_state_t *s, void *user_data, int indicator);
+typedef int (*t38_rx_data_handler_t)(t38_core_state_t *s, void *user_data, int data_type, int field_type, const uint8_t *buf, int len);
+typedef int (*t38_rx_missing_handler_t)(t38_core_state_t *s, void *user_data, int rx_seq_no, int expected_seq_no);
 
 #if defined(__cplusplus)
 extern "C"
@@ -398,11 +398,11 @@ SPAN_DECLARE(int) t38_core_restart(t38_core_state_t *s);
     \param tx_packet_user_data An opaque pointer passed to the tx_packet_handler.
     \return A pointer to the T.38 context, or NULL if there was a problem. */
 SPAN_DECLARE(t38_core_state_t *) t38_core_init(t38_core_state_t *s,
-                                               t38_rx_indicator_handler_t *rx_indicator_handler,
-                                               t38_rx_data_handler_t *rx_data_handler,
-                                               t38_rx_missing_handler_t *rx_missing_handler,
+                                               t38_rx_indicator_handler_t rx_indicator_handler,
+                                               t38_rx_data_handler_t rx_data_handler,
+                                               t38_rx_missing_handler_t rx_missing_handler,
                                                void *rx_user_data,
-                                               t38_tx_packet_handler_t *tx_packet_handler,
+                                               t38_tx_packet_handler_t tx_packet_handler,
                                                void *tx_packet_user_data);
 
 /*! Release a signaling tone transmitter context.
diff --git a/libs/spandsp/src/spandsp/t38_gateway.h b/libs/spandsp/src/spandsp/t38_gateway.h
index fa6db4bec5..d6bfc39555 100644
--- a/libs/spandsp/src/spandsp/t38_gateway.h
+++ b/libs/spandsp/src/spandsp/t38_gateway.h
@@ -56,11 +56,11 @@ typedef struct t38_gateway_state_s t38_gateway_state_t;
     \param msg The HDLC message.
     \param len The length of the message.
 */
-typedef void (t38_gateway_real_time_frame_handler_t)(t38_gateway_state_t *s,
-                                                     void *user_data,
-                                                     int direction,
-                                                     const uint8_t *msg,
-                                                     int len);
+typedef void (*t38_gateway_real_time_frame_handler_t)(t38_gateway_state_t *s,
+                                                      void *user_data,
+                                                      int direction,
+                                                      const uint8_t *msg,
+                                                      int len);
 
 /*!
     T.38 gateway results.
@@ -86,7 +86,7 @@ extern "C"
     \param tx_packet_user_data An opaque pointer passed to the tx_packet_handler routine.
     \return A pointer to the termination mode T.38 context, or NULL if there was a problem. */
 SPAN_DECLARE(t38_gateway_state_t *) t38_gateway_init(t38_gateway_state_t *s,
-                                                     t38_tx_packet_handler_t *tx_packet_handler,
+                                                     t38_tx_packet_handler_t tx_packet_handler,
                                                      void *tx_packet_user_data);
 
 /*! Release a gateway mode T.38 context.
@@ -212,7 +212,7 @@ SPAN_DECLARE(logging_state_t *) t38_gateway_get_logging_state(t38_gateway_state_
     \param handler The callback function.
     \param user_data An opaque pointer passed to the callback function. */
 SPAN_DECLARE(void) t38_gateway_set_real_time_frame_handler(t38_gateway_state_t *s,
-                                                           t38_gateway_real_time_frame_handler_t *handler,
+                                                           t38_gateway_real_time_frame_handler_t handler,
                                                            void *user_data);
 
 #if defined(__cplusplus)
diff --git a/libs/spandsp/src/spandsp/t38_terminal.h b/libs/spandsp/src/spandsp/t38_terminal.h
index 2307f765f7..a847d96cf3 100644
--- a/libs/spandsp/src/spandsp/t38_terminal.h
+++ b/libs/spandsp/src/spandsp/t38_terminal.h
@@ -123,7 +123,7 @@ SPAN_DECLARE(int) t38_terminal_restart(t38_terminal_state_t *s,
     \return A pointer to the termination mode T.38 context, or NULL if there was a problem. */
 SPAN_DECLARE(t38_terminal_state_t *) t38_terminal_init(t38_terminal_state_t *s,
                                                        int calling_party,
-                                                       t38_tx_packet_handler_t *tx_packet_handler,
+                                                       t38_tx_packet_handler_t tx_packet_handler,
                                                        void *tx_packet_user_data);
 
 /*! Release a termination mode T.38 context.
diff --git a/libs/spandsp/src/spandsp/telephony.h b/libs/spandsp/src/spandsp/telephony.h
index 49d7200e83..7a09bbe044 100644
--- a/libs/spandsp/src/spandsp/telephony.h
+++ b/libs/spandsp/src/spandsp/telephony.h
@@ -56,16 +56,16 @@
 #define DBOV_MAX_SINE_POWER         (-3.02f)
 
 /*! \brief A handler for pure receive. The buffer cannot be altered. */
-typedef int (span_rx_handler_t)(void *s, const int16_t amp[], int len);
+typedef int (*span_rx_handler_t)(void *s, const int16_t amp[], int len);
 
 /*! \brief A handler for receive, where the buffer can be altered. */
-typedef int (span_mod_handler_t)(void *s, int16_t amp[], int len);
+typedef int (*span_mod_handler_t)(void *s, int16_t amp[], int len);
 
 /*! \brief A handler for missing receive data fill-in. */
-typedef int (span_rx_fillin_handler_t)(void *s, int len);
+typedef int (*span_rx_fillin_handler_t)(void *s, int len);
 
 /*! \brief A handler for transmit, where the buffer will be filled. */
-typedef int (span_tx_handler_t)(void *s, int16_t amp[], int max_len);
+typedef int (*span_tx_handler_t)(void *s, int16_t amp[], int max_len);
 
 #define ms_to_samples(t)            ((t)*(SAMPLE_RATE/1000))
 #define us_to_samples(t)            ((t)/(1000000/SAMPLE_RATE))
diff --git a/libs/spandsp/src/spandsp/v8.h b/libs/spandsp/src/spandsp/v8.h
index 25449fb6c1..152c478fad 100644
--- a/libs/spandsp/src/spandsp/v8.h
+++ b/libs/spandsp/src/spandsp/v8.h
@@ -43,7 +43,7 @@ being negotiating and training with their chosen modem standard.
 
 typedef struct v8_parms_s v8_parms_t;
 
-typedef void (v8_result_handler_t)(void *user_data, v8_parms_t *result);
+typedef void (*v8_result_handler_t)(void *user_data, v8_parms_t *result);
 
 enum v8_call_function_e
 {
@@ -147,7 +147,7 @@ SPAN_DECLARE(int) v8_restart(v8_state_t *s,
 SPAN_DECLARE(v8_state_t *) v8_init(v8_state_t *s,
                                    int calling_party,
                                    v8_parms_t *parms,
-                                   v8_result_handler_t *result_handler,
+                                   v8_result_handler_t result_handler,
                                    void *user_data);
 
 /*! Release a V.8 context.
diff --git a/libs/spandsp/src/t30.c b/libs/spandsp/src/t30.c
index 92564fcb0e..e95a75f15a 100644
--- a/libs/spandsp/src/t30.c
+++ b/libs/spandsp/src/t30.c
@@ -6345,11 +6345,11 @@ SPAN_DECLARE(int) t30_restart(t30_state_t *s)
 
 SPAN_DECLARE(t30_state_t *) t30_init(t30_state_t *s,
                                      int calling_party,
-                                     t30_set_handler_t *set_rx_type_handler,
+                                     t30_set_handler_t set_rx_type_handler,
                                      void *set_rx_type_user_data,
-                                     t30_set_handler_t *set_tx_type_handler,
+                                     t30_set_handler_t set_tx_type_handler,
                                      void *set_tx_type_user_data,
-                                     t30_send_hdlc_handler_t *send_hdlc_handler,
+                                     t30_send_hdlc_handler_t send_hdlc_handler,
                                      void *send_hdlc_user_data)
 {
     if (s == NULL)
diff --git a/libs/spandsp/src/t30_api.c b/libs/spandsp/src/t30_api.c
index 8ba35e5732..c1ee907477 100644
--- a/libs/spandsp/src/t30_api.c
+++ b/libs/spandsp/src/t30_api.c
@@ -765,35 +765,35 @@ SPAN_DECLARE(int) t30_set_receiver_not_ready(t30_state_t *s, int count)
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) t30_set_phase_b_handler(t30_state_t *s, t30_phase_b_handler_t *handler, void *user_data)
+SPAN_DECLARE(void) t30_set_phase_b_handler(t30_state_t *s, t30_phase_b_handler_t handler, void *user_data)
 {
     s->phase_b_handler = handler;
     s->phase_b_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) t30_set_phase_d_handler(t30_state_t *s, t30_phase_d_handler_t *handler, void *user_data)
+SPAN_DECLARE(void) t30_set_phase_d_handler(t30_state_t *s, t30_phase_d_handler_t handler, void *user_data)
 {
     s->phase_d_handler = handler;
     s->phase_d_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) t30_set_phase_e_handler(t30_state_t *s, t30_phase_e_handler_t *handler, void *user_data)
+SPAN_DECLARE(void) t30_set_phase_e_handler(t30_state_t *s, t30_phase_e_handler_t handler, void *user_data)
 {
     s->phase_e_handler = handler;
     s->phase_e_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) t30_set_document_handler(t30_state_t *s, t30_document_handler_t *handler, void *user_data)
+SPAN_DECLARE(void) t30_set_document_handler(t30_state_t *s, t30_document_handler_t handler, void *user_data)
 {
     s->document_handler = handler;
     s->document_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-SPAN_DECLARE(void) t30_set_real_time_frame_handler(t30_state_t *s, t30_real_time_frame_handler_t *handler, void *user_data)
+SPAN_DECLARE(void) t30_set_real_time_frame_handler(t30_state_t *s, t30_real_time_frame_handler_t handler, void *user_data)
 {
     s->real_time_frame_handler = handler;
     s->real_time_frame_user_data = user_data;
diff --git a/libs/spandsp/src/t31.c b/libs/spandsp/src/t31.c
index bc18a72e59..2ed6a9e24d 100644
--- a/libs/spandsp/src/t31.c
+++ b/libs/spandsp/src/t31.c
@@ -186,9 +186,9 @@ enum
 
 static int restart_modem(t31_state_t *s, int new_modem);
 static void hdlc_accept_frame(void *user_data, const uint8_t *msg, int len, int ok);
-static void set_rx_handler(t31_state_t *s, span_rx_handler_t *rx_handler, span_rx_fillin_handler_t *fillin_handler, void *user_data);
-static void set_tx_handler(t31_state_t *s, span_tx_handler_t *handler, void *user_data);
-static void set_next_tx_handler(t31_state_t *s, span_tx_handler_t *handler, void *user_data);
+static void set_rx_handler(t31_state_t *s, span_rx_handler_t rx_handler, span_rx_fillin_handler_t fillin_handler, void *user_data);
+static void set_tx_handler(t31_state_t *s, span_tx_handler_t handler, void *user_data);
+static void set_next_tx_handler(t31_state_t *s, span_tx_handler_t handler, void *user_data);
 static int v17_v21_rx(void *user_data, const int16_t amp[], int len);
 static int v17_v21_rx_fillin(void *user_data, int len);
 static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len);
@@ -1327,6 +1327,7 @@ static void tone_detected(void *user_data, int tone, int level, int delay)
 }
 /*- End of function --------------------------------------------------------*/
 
+#if 0
 static void v8_handler(void *user_data, v8_parms_t *result)
 {
     t31_state_t *s;
@@ -1335,6 +1336,7 @@ static void v8_handler(void *user_data, v8_parms_t *result)
     span_log(&s->logging, SPAN_LOG_FLOW, "V.8 report received\n");
 }
 /*- End of function --------------------------------------------------------*/
+#endif
 
 static void hdlc_tx_underflow(void *user_data)
 {
@@ -1564,7 +1566,7 @@ static int restart_modem(t31_state_t *s, int new_modem)
     s->at_state.rx_signal_present = FALSE;
     s->at_state.rx_trained = FALSE;
     s->rx_frame_received = FALSE;
-    set_rx_handler(s, (span_rx_handler_t *) &span_dummy_rx, (span_rx_fillin_handler_t *) &span_dummy_rx_fillin, NULL);
+    set_rx_handler(s, (span_rx_handler_t) &span_dummy_rx, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, NULL);
     use_hdlc = FALSE;
     switch (s->modem)
     {
@@ -1583,10 +1585,10 @@ static int restart_modem(t31_state_t *s, int new_modem)
             /* Do V.21/HDLC receive in parallel. The other end may send its
                first message at any time. The CNG tone will continue until
                we get a valid preamble. */
-            set_rx_handler(s, (span_rx_handler_t *) &cng_rx, (span_rx_fillin_handler_t *) &span_dummy_rx_fillin, s);
+            set_rx_handler(s, (span_rx_handler_t) &cng_rx, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, s);
             t31_v21_rx(s);
-            set_tx_handler(s, (span_tx_handler_t *) &modem_connect_tones_tx, &t->connect_tx);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->at_state.transmit = TRUE;
         break;
@@ -1596,10 +1598,10 @@ static int restart_modem(t31_state_t *s, int new_modem)
         }
         else
         {
-            set_rx_handler(s, (span_rx_handler_t *) &cng_rx, (span_rx_fillin_handler_t *) &span_dummy_rx_fillin, s);
+            set_rx_handler(s, (span_rx_handler_t) &cng_rx, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, s);
             t31_v21_rx(s);
             silence_gen_set(&t->silence_gen, 0);
-            set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
+            set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
         }
         s->at_state.transmit = FALSE;
         break;
@@ -1613,8 +1615,8 @@ static int restart_modem(t31_state_t *s, int new_modem)
         else
         {
             modem_connect_tones_tx_init(&t->connect_tx, MODEM_CONNECT_TONES_FAX_CED);
-            set_tx_handler(s, (span_tx_handler_t *) &modem_connect_tones_tx, &t->connect_tx);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->at_state.transmit = TRUE;
         break;
@@ -1633,8 +1635,8 @@ static int restart_modem(t31_state_t *s, int new_modem)
             /* The spec says 1s +-15% of preamble. So, the minimum is 32 octets. */
             hdlc_tx_flags(&t->hdlc_tx, 32);
             fsk_tx_init(&t->v21_tx, &preset_fsk_specs[FSK_V21CH2], (get_bit_func_t) hdlc_tx_get_bit, &t->hdlc_tx);
-            set_tx_handler(s, (span_tx_handler_t *) &fsk_tx, &t->v21_tx);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &fsk_tx, &t->v21_tx);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->hdlc_tx.final = FALSE;
         s->hdlc_tx.len = 0;
@@ -1647,7 +1649,7 @@ static int restart_modem(t31_state_t *s, int new_modem)
         }
         else
         {
-            set_rx_handler(s, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &t->v21_rx);
+            set_rx_handler(s, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &t->v21_rx);
             t31_v21_rx(s);
         }
         break;
@@ -1679,8 +1681,8 @@ static int restart_modem(t31_state_t *s, int new_modem)
         else
         {
             v17_tx_restart(&t->fast_modems.v17_tx, s->bit_rate, FALSE, s->short_train);
-            set_tx_handler(s, (span_tx_handler_t *) &v17_tx, &t->fast_modems.v17_tx);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &v17_tx, &t->fast_modems.v17_tx);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->tx.out_bytes = 0;
         s->tx.data_started = FALSE;
@@ -1689,7 +1691,7 @@ static int restart_modem(t31_state_t *s, int new_modem)
     case FAX_MODEM_V17_RX:
         if (!s->t38_mode)
         {
-            set_rx_handler(s, (span_rx_handler_t *) &v17_v21_rx, (span_rx_fillin_handler_t *) &v17_v21_rx_fillin, s);
+            set_rx_handler(s, (span_rx_handler_t) &v17_v21_rx, (span_rx_fillin_handler_t) &v17_v21_rx_fillin, s);
             v17_rx_restart(&t->fast_modems.v17_rx, s->bit_rate, s->short_train);
             /* Allow for +FCERROR/+FRH:3 */
             t31_v21_rx(s);
@@ -1716,8 +1718,8 @@ static int restart_modem(t31_state_t *s, int new_modem)
         else
         {
             v27ter_tx_restart(&t->fast_modems.v27ter_tx, s->bit_rate, FALSE);
-            set_tx_handler(s, (span_tx_handler_t *) &v27ter_tx, &t->fast_modems.v27ter_tx);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &v27ter_tx, &t->fast_modems.v27ter_tx);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->tx.out_bytes = 0;
         s->tx.data_started = FALSE;
@@ -1726,7 +1728,7 @@ static int restart_modem(t31_state_t *s, int new_modem)
     case FAX_MODEM_V27TER_RX:
         if (!s->t38_mode)
         {
-            set_rx_handler(s, (span_rx_handler_t *) &v27ter_v21_rx, (span_rx_fillin_handler_t *) &v27ter_v21_rx_fillin, s);
+            set_rx_handler(s, (span_rx_handler_t) &v27ter_v21_rx, (span_rx_fillin_handler_t) &v27ter_v21_rx_fillin, s);
             v27ter_rx_restart(&t->fast_modems.v27ter_rx, s->bit_rate, FALSE);
             /* Allow for +FCERROR/+FRH:3 */
             t31_v21_rx(s);
@@ -1753,8 +1755,8 @@ static int restart_modem(t31_state_t *s, int new_modem)
         else
         {
             v29_tx_restart(&t->fast_modems.v29_tx, s->bit_rate, FALSE);
-            set_tx_handler(s, (span_tx_handler_t *) &v29_tx, &t->fast_modems.v29_tx);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &v29_tx, &t->fast_modems.v29_tx);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->tx.out_bytes = 0;
         s->tx.data_started = FALSE;
@@ -1763,7 +1765,7 @@ static int restart_modem(t31_state_t *s, int new_modem)
     case FAX_MODEM_V29_RX:
         if (!s->t38_mode)
         {
-            set_rx_handler(s, (span_rx_handler_t *) &v29_v21_rx, (span_rx_fillin_handler_t *) &v29_v21_rx_fillin, s);
+            set_rx_handler(s, (span_rx_handler_t) &v29_v21_rx, (span_rx_fillin_handler_t) &v29_v21_rx_fillin, s);
             v29_rx_restart(&t->fast_modems.v29_rx, s->bit_rate, FALSE);
             /* Allow for +FCERROR/+FRH:3 */
             t31_v21_rx(s);
@@ -1781,18 +1783,18 @@ static int restart_modem(t31_state_t *s, int new_modem)
         else
         {
             silence_gen_set(&t->silence_gen, 0);
-            set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->at_state.transmit = FALSE;
         break;
     case FAX_MODEM_SILENCE_RX:
         if (!s->t38_mode)
         {
-            set_rx_handler(s, (span_rx_handler_t *) &silence_rx, (span_rx_fillin_handler_t *) &span_dummy_rx_fillin, s);
+            set_rx_handler(s, (span_rx_handler_t) &silence_rx, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, s);
             silence_gen_set(&t->silence_gen, 0);
-            set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         }
         s->at_state.transmit = FALSE;
         break;
@@ -1806,8 +1808,8 @@ static int restart_modem(t31_state_t *s, int new_modem)
         {
             s->modem = FAX_MODEM_SILENCE_TX;
             silence_gen_alter(&t->silence_gen, ms_to_samples(200));
-            set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-            set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+            set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+            set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
             s->at_state.transmit = TRUE;
         }
         break;
@@ -2150,7 +2152,7 @@ SPAN_DECLARE(int) t31_at_rx(t31_state_t *s, const char *t, int len)
             s->at_state.rx_data_bytes = 0;
             s->at_state.transmit = FALSE;
             s->modem = FAX_MODEM_SILENCE_TX;
-            set_rx_handler(s, (span_rx_handler_t *) &span_dummy_rx, (span_rx_fillin_handler_t *) &span_dummy_rx_fillin, NULL);
+            set_rx_handler(s, (span_rx_handler_t) &span_dummy_rx, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, NULL);
             t31_set_at_rx_mode(s, AT_MODE_OFFHOOK_COMMAND);
             at_put_response_code(&s->at_state, AT_RESPONSE_CODE_OK);
         }
@@ -2177,8 +2179,8 @@ SPAN_DECLARE(int) t31_at_rx(t31_state_t *s, const char *t, int len)
 /*- End of function --------------------------------------------------------*/
 
 static void set_rx_handler(t31_state_t *s,
-                           span_rx_handler_t *rx_handler,
-                           span_rx_fillin_handler_t *fillin_handler,
+                           span_rx_handler_t rx_handler,
+                           span_rx_fillin_handler_t fillin_handler,
                            void *user_data)
 {
     s->audio.modems.rx_handler = rx_handler;
@@ -2187,14 +2189,14 @@ static void set_rx_handler(t31_state_t *s,
 }
 /*- End of function --------------------------------------------------------*/
 
-static void set_tx_handler(t31_state_t *s, span_tx_handler_t *handler, void *user_data)
+static void set_tx_handler(t31_state_t *s, span_tx_handler_t handler, void *user_data)
 {
     s->audio.modems.tx_handler = handler;
     s->audio.modems.tx_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-static void set_next_tx_handler(t31_state_t *s, span_tx_handler_t *handler, void *user_data)
+static void set_next_tx_handler(t31_state_t *s, span_tx_handler_t handler, void *user_data)
 {
     s->audio.modems.next_tx_handler = handler;
     s->audio.modems.next_tx_user_data = user_data;
@@ -2252,7 +2254,7 @@ static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.17 (%.2fdBm0)\n", v17_rx_signal_power(&s->fast_modems.v17_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v17_rx, (span_rx_fillin_handler_t *) &v17_rx_fillin, &s->fast_modems.v17_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v17_rx, (span_rx_fillin_handler_t) &v17_rx_fillin, &s->fast_modems.v17_rx);
     }
     else
     {
@@ -2262,7 +2264,7 @@ static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
             /* We have received something, and the fast modem has not trained. We must
                be receiving valid V.21 */
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
     }
     return len;
@@ -2295,7 +2297,7 @@ static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.27ter (%.2fdBm0)\n", v27ter_rx_signal_power(&s->fast_modems.v27ter_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v27ter_rx, (span_rx_fillin_handler_t *) &v27ter_rx_fillin, &s->fast_modems.v27ter_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v27ter_rx, (span_rx_fillin_handler_t) &v27ter_rx_fillin, &s->fast_modems.v27ter_rx);
     }
     else
     {
@@ -2305,7 +2307,7 @@ static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
             /* We have received something, and the fast modem has not trained. We must
                be receiving valid V.21 */
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
     }
     return len;
@@ -2338,7 +2340,7 @@ static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&s->fast_modems.v29_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v29_rx, (span_rx_fillin_handler_t *) &v29_rx_fillin, &s->fast_modems.v29_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v29_rx, (span_rx_fillin_handler_t) &v29_rx_fillin, &s->fast_modems.v29_rx);
     }
     else
     {
@@ -2348,7 +2350,7 @@ static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
             /* We have received something, and the fast modem has not trained. We must
                be receiving valid V.21 */
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
     }
     return len;
@@ -2461,13 +2463,13 @@ static int set_next_tx_type(t31_state_t *s)
     if (s->audio.next_tx_handler)
     {
         set_tx_handler(s, s->audio.next_tx_handler, s->audio.next_tx_user_data);
-        set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+        set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         return 0;
     }
     /* There is nothing else to change to, so use zero length silence */
     silence_gen_alter(&s->audio.modems.silence_gen, 0);
-    set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &s->audio.modems.silence_gen);
-    set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+    set_tx_handler(s, (span_tx_handler_t) &silence_gen, &s->audio.modems.silence_gen);
+    set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
     return -1;
 }
 /*- End of function --------------------------------------------------------*/
@@ -2556,7 +2558,7 @@ SPAN_DECLARE(t38_core_state_t *) t31_get_t38_core_state(t31_state_t *s)
 /*- End of function --------------------------------------------------------*/
 
 static int t31_t38_fe_init(t31_state_t *t,
-                           t38_tx_packet_handler_t *tx_packet_handler,
+                           t38_tx_packet_handler_t tx_packet_handler,
                            void *tx_packet_user_data)
 {
     t31_t38_front_end_state_t *s;
@@ -2589,11 +2591,11 @@ static int t31_t38_fe_init(t31_state_t *t,
 /*- End of function --------------------------------------------------------*/
 
 SPAN_DECLARE(t31_state_t *) t31_init(t31_state_t *s,
-                                     at_tx_handler_t *at_tx_handler,
+                                     at_tx_handler_t at_tx_handler,
                                      void *at_tx_user_data,
-                                     t31_modem_control_handler_t *modem_control_handler,
+                                     t31_modem_control_handler_t modem_control_handler,
                                      void *modem_control_user_data,
-                                     t38_tx_packet_handler_t *tx_t38_packet_handler,
+                                     t38_tx_packet_handler_t tx_t38_packet_handler,
                                      void *tx_t38_packet_user_data)
 {
 #if 0
diff --git a/libs/spandsp/src/t38_core.c b/libs/spandsp/src/t38_core.c
index 67a53ae707..4a81b0eda1 100644
--- a/libs/spandsp/src/t38_core.c
+++ b/libs/spandsp/src/t38_core.c
@@ -1100,11 +1100,11 @@ SPAN_DECLARE(int) t38_core_restart(t38_core_state_t *s)
 /*- End of function --------------------------------------------------------*/
 
 SPAN_DECLARE(t38_core_state_t *) t38_core_init(t38_core_state_t *s,
-                                               t38_rx_indicator_handler_t *rx_indicator_handler,
-                                               t38_rx_data_handler_t *rx_data_handler,
-                                               t38_rx_missing_handler_t *rx_missing_handler,
+                                               t38_rx_indicator_handler_t rx_indicator_handler,
+                                               t38_rx_data_handler_t rx_data_handler,
+                                               t38_rx_missing_handler_t rx_missing_handler,
                                                void *rx_user_data,
-                                               t38_tx_packet_handler_t *tx_packet_handler,
+                                               t38_tx_packet_handler_t tx_packet_handler,
                                                void *tx_packet_user_data)
 {
     if (s == NULL)
diff --git a/libs/spandsp/src/t38_gateway.c b/libs/spandsp/src/t38_gateway.c
index 85022b8d54..4c0c5a59da 100644
--- a/libs/spandsp/src/t38_gateway.c
+++ b/libs/spandsp/src/t38_gateway.c
@@ -206,7 +206,7 @@ static void non_ecm_remove_fill_and_put_bit(void *user_data, int bit);
 static void non_ecm_push_residue(t38_gateway_state_t *s);
 static void tone_detected(void *user_data, int tone, int level, int delay);
 
-static void set_rx_handler(t38_gateway_state_t *s, span_rx_handler_t *handler, span_rx_fillin_handler_t *fillin_handler, void *user_data)
+static void set_rx_handler(t38_gateway_state_t *s, span_rx_handler_t handler, span_rx_fillin_handler_t fillin_handler, void *user_data)
 {
     if (s->audio.modems.rx_handler != span_dummy_rx)
     {
@@ -220,14 +220,14 @@ static void set_rx_handler(t38_gateway_state_t *s, span_rx_handler_t *handler, s
 }
 /*- End of function --------------------------------------------------------*/
 
-static void set_tx_handler(t38_gateway_state_t *s, span_tx_handler_t *handler, void *user_data)
+static void set_tx_handler(t38_gateway_state_t *s, span_tx_handler_t handler, void *user_data)
 {
     s->audio.modems.tx_handler = handler;
     s->audio.modems.tx_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-static void set_next_tx_handler(t38_gateway_state_t *s, span_tx_handler_t *handler, void *user_data)
+static void set_next_tx_handler(t38_gateway_state_t *s, span_tx_handler_t handler, void *user_data)
 {
     s->audio.modems.next_tx_handler = handler;
     s->audio.modems.next_tx_user_data = user_data;
@@ -267,7 +267,7 @@ static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.17 (%.2fdBm0)\n", v17_rx_signal_power(&s->fast_modems.v17_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v17_rx, (span_rx_fillin_handler_t *) &v17_rx_fillin, &s->fast_modems.v17_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v17_rx, (span_rx_fillin_handler_t) &v17_rx_fillin, &s->fast_modems.v17_rx);
     }
     else
     {
@@ -275,7 +275,7 @@ static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
         if (s->rx_signal_present)
         {
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
         /*endif*/
     }
@@ -310,7 +310,7 @@ static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.27ter (%.2fdBm0)\n", v27ter_rx_signal_power(&s->fast_modems.v27ter_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v27ter_rx, (span_rx_fillin_handler_t *) &v27ter_v21_rx_fillin, &s->fast_modems.v27ter_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v27ter_rx, (span_rx_fillin_handler_t) &v27ter_v21_rx_fillin, &s->fast_modems.v27ter_rx);
     }
     else
     {
@@ -318,7 +318,7 @@ static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
         if (s->rx_signal_present)
         {
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
         /*endif*/
     }
@@ -353,7 +353,7 @@ static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&s->fast_modems.v29_rx));
-        set_rx_handler(t, (span_rx_handler_t *) &v29_rx, (span_rx_fillin_handler_t *) &v29_rx_fillin, &s->fast_modems.v29_rx);
+        set_rx_handler(t, (span_rx_handler_t) &v29_rx, (span_rx_fillin_handler_t) &v29_rx_fillin, &s->fast_modems.v29_rx);
     }
     else
     {
@@ -361,7 +361,7 @@ static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
         if (s->rx_signal_present)
         {
             span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
-            set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx);
+            set_rx_handler(t, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         }
         /*endif*/
     }
@@ -440,9 +440,9 @@ static int set_next_tx_type(t38_gateway_state_t *s)
         /* There is a handler queued, so that is the next one. */
         set_tx_handler(s, t->next_tx_handler, t->next_tx_user_data);
         set_next_tx_handler(s, NULL, NULL);
-        if (t->tx_handler == (span_tx_handler_t *) &(silence_gen)
+        if (t->tx_handler == (span_tx_handler_t) &(silence_gen)
             ||
-            t->tx_handler == (span_tx_handler_t *) &(tone_gen))
+            t->tx_handler == (span_tx_handler_t) &(tone_gen))
         {
             set_rx_active(s, TRUE);
         }
@@ -489,23 +489,23 @@ static int set_next_tx_type(t38_gateway_state_t *s)
         t->tx_bit_rate = 0;
         /* Impose 75ms minimum on transmitted silence */
         //silence_gen_set(&t->silence_gen, ms_to_samples(75));
-        set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+        set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         set_rx_active(s, TRUE);
         break;
     case T38_IND_CNG:
         t->tx_bit_rate = 0;
         modem_connect_tones_tx_init(&t->connect_tx, MODEM_CONNECT_TONES_FAX_CNG);
-        set_tx_handler(s, (span_tx_handler_t *) &modem_connect_tones_tx, &t->connect_tx);
+        set_tx_handler(s, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
         silence_gen_set(&t->silence_gen, 0);
-        set_next_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
+        set_next_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
         set_rx_active(s, TRUE);
         break;
     case T38_IND_CED:
         t->tx_bit_rate = 0;
         modem_connect_tones_tx_init(&t->connect_tx, MODEM_CONNECT_TONES_FAX_CED);
-        set_tx_handler(s, (span_tx_handler_t *) &modem_connect_tones_tx, &t->connect_tx);
-        set_next_tx_handler(s, (span_tx_handler_t *) NULL, NULL);
+        set_tx_handler(s, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+        set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         set_rx_active(s, TRUE);
         break;
     case T38_IND_V21_PREAMBLE:
@@ -515,8 +515,8 @@ static int set_next_tx_type(t38_gateway_state_t *s)
         silence_gen_alter(&t->silence_gen, ms_to_samples(75));
         u->buf[u->in].len = 0;
         fsk_tx_init(&t->v21_tx, &preset_fsk_specs[FSK_V21CH2], (get_bit_func_t) hdlc_tx_get_bit, &t->hdlc_tx);
-        set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        set_next_tx_handler(s, (span_tx_handler_t *) &fsk_tx, &t->v21_tx);
+        set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        set_next_tx_handler(s, (span_tx_handler_t) &fsk_tx, &t->v21_tx);
         set_rx_active(s, TRUE);
         break;
     case T38_IND_V27TER_2400_TRAINING:
@@ -534,8 +534,8 @@ static int set_next_tx_type(t38_gateway_state_t *s)
         silence_gen_alter(&t->silence_gen, ms_to_samples(75));
         v27ter_tx_restart(&t->fast_modems.v27ter_tx, t->tx_bit_rate, t->use_tep);
         v27ter_tx_set_get_bit(&t->fast_modems.v27ter_tx, get_bit_func, get_bit_user_data);
-        set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        set_next_tx_handler(s, (span_tx_handler_t *) &v27ter_tx, &t->fast_modems.v27ter_tx);
+        set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        set_next_tx_handler(s, (span_tx_handler_t) &v27ter_tx, &t->fast_modems.v27ter_tx);
         set_rx_active(s, TRUE);
         break;
     case T38_IND_V29_7200_TRAINING:
@@ -553,8 +553,8 @@ static int set_next_tx_type(t38_gateway_state_t *s)
         silence_gen_alter(&t->silence_gen, ms_to_samples(75));
         v29_tx_restart(&t->fast_modems.v29_tx, t->tx_bit_rate, t->use_tep);
         v29_tx_set_get_bit(&t->fast_modems.v29_tx, get_bit_func, get_bit_user_data);
-        set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        set_next_tx_handler(s, (span_tx_handler_t *) &v29_tx, &t->fast_modems.v29_tx);
+        set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        set_next_tx_handler(s, (span_tx_handler_t) &v29_tx, &t->fast_modems.v29_tx);
         set_rx_active(s, TRUE);
         break;
     case T38_IND_V17_7200_SHORT_TRAINING:
@@ -601,8 +601,8 @@ static int set_next_tx_type(t38_gateway_state_t *s)
         silence_gen_alter(&t->silence_gen, ms_to_samples(75));
         v17_tx_restart(&t->fast_modems.v17_tx, t->tx_bit_rate, t->use_tep, short_train);
         v17_tx_set_get_bit(&t->fast_modems.v17_tx, get_bit_func, get_bit_user_data);
-        set_tx_handler(s, (span_tx_handler_t *) &silence_gen, &t->silence_gen);
-        set_next_tx_handler(s, (span_tx_handler_t *) &v17_tx, &t->fast_modems.v17_tx);
+        set_tx_handler(s, (span_tx_handler_t) &silence_gen, &t->silence_gen);
+        set_next_tx_handler(s, (span_tx_handler_t) &v17_tx, &t->fast_modems.v17_tx);
         set_rx_active(s, TRUE);
         break;
     case T38_IND_V8_ANSAM:
@@ -2185,7 +2185,7 @@ static int restart_rx_modem(t38_gateway_state_t *s)
         s->core.fast_rx_active = FAX_MODEM_V17_RX;
         break;
     default:
-        set_rx_handler(s, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &t->v21_rx);
+        set_rx_handler(s, (span_rx_handler_t) &fsk_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &t->v21_rx);
         s->core.fast_rx_active = FAX_MODEM_NONE;
         break;
     }
@@ -2393,7 +2393,7 @@ SPAN_DECLARE(void) t38_gateway_set_fill_bit_removal(t38_gateway_state_t *s, int
 /*- End of function --------------------------------------------------------*/
 
 SPAN_DECLARE(void) t38_gateway_set_real_time_frame_handler(t38_gateway_state_t *s,
-                                                           t38_gateway_real_time_frame_handler_t *handler,
+                                                           t38_gateway_real_time_frame_handler_t handler,
                                                            void *user_data)
 {
     s->core.real_time_frame_handler = handler;
@@ -2424,7 +2424,7 @@ static int t38_gateway_audio_init(t38_gateway_state_t *s)
 /*- End of function --------------------------------------------------------*/
 
 static int t38_gateway_t38_init(t38_gateway_state_t *t,
-                                t38_tx_packet_handler_t *tx_packet_handler,
+                                t38_tx_packet_handler_t tx_packet_handler,
                                 void *tx_packet_user_data)
 {
     t38_gateway_t38_state_t *s;
@@ -2447,7 +2447,7 @@ static int t38_gateway_t38_init(t38_gateway_state_t *t,
 /*- End of function --------------------------------------------------------*/
 
 SPAN_DECLARE(t38_gateway_state_t *) t38_gateway_init(t38_gateway_state_t *s,
-                                                     t38_tx_packet_handler_t *tx_packet_handler,
+                                                     t38_tx_packet_handler_t tx_packet_handler,
                                                      void *tx_packet_user_data)
 {
     if (tx_packet_handler == NULL)
diff --git a/libs/spandsp/src/t38_terminal.c b/libs/spandsp/src/t38_terminal.c
index 1efa1b09d6..b66e9ce409 100644
--- a/libs/spandsp/src/t38_terminal.c
+++ b/libs/spandsp/src/t38_terminal.c
@@ -1446,7 +1446,7 @@ static int t38_terminal_t38_fe_restart(t38_terminal_state_t *t)
 /*- End of function --------------------------------------------------------*/
 
 static int t38_terminal_t38_fe_init(t38_terminal_state_t *t,
-                                    t38_tx_packet_handler_t *tx_packet_handler,
+                                    t38_tx_packet_handler_t tx_packet_handler,
                                     void *tx_packet_user_data)
 {
     t38_terminal_front_end_state_t *s;
@@ -1495,7 +1495,7 @@ SPAN_DECLARE(int) t38_terminal_restart(t38_terminal_state_t *s,
 
 SPAN_DECLARE(t38_terminal_state_t *) t38_terminal_init(t38_terminal_state_t *s,
                                                        int calling_party,
-                                                       t38_tx_packet_handler_t *tx_packet_handler,
+                                                       t38_tx_packet_handler_t tx_packet_handler,
                                                        void *tx_packet_user_data)
 {
     if (tx_packet_handler == NULL)
diff --git a/libs/spandsp/src/v8.c b/libs/spandsp/src/v8.c
index 906f96ba95..8ac13d3dd8 100644
--- a/libs/spandsp/src/v8.c
+++ b/libs/spandsp/src/v8.c
@@ -1040,7 +1040,7 @@ SPAN_DECLARE(int) v8_restart(v8_state_t *s, int calling_party, v8_parms_t *parms
 SPAN_DECLARE(v8_state_t *) v8_init(v8_state_t *s,
                                    int calling_party,
                                    v8_parms_t *parms,
-                                   v8_result_handler_t *result_handler,
+                                   v8_result_handler_t result_handler,
                                    void *user_data)
 {
     if (s == NULL)
diff --git a/libs/spandsp/test-data/etsi/fax/generate_etsi_300_242_pages.c b/libs/spandsp/test-data/etsi/fax/generate_etsi_300_242_pages.c
index d7cefc6778..dda0d0fbc7 100644
--- a/libs/spandsp/test-data/etsi/fax/generate_etsi_300_242_pages.c
+++ b/libs/spandsp/test-data/etsi/fax/generate_etsi_300_242_pages.c
@@ -543,7 +543,6 @@ static int create_error_page(TIFF *tiff_file)
 
 int main(int argc, char *argv[])
 {
-    int row;
     TIFF *tiff_file;
     struct tm *tm;
     time_t now;
@@ -553,24 +552,13 @@ int main(int argc, char *argv[])
     int i;
     int image_length;
     int opt;
-    int compression;
 
-    compression = T4_COMPRESSION_ITU_T6;
     photo_metric = PHOTOMETRIC_MINISWHITE;
     fill_order = FILLORDER_LSB2MSB;
-    while ((opt = getopt(argc, argv, "126ir")) != -1)
+    while ((opt = getopt(argc, argv, "ir")) != -1)
     {
         switch (opt)
         {
-        case '1':
-            compression = T4_COMPRESSION_ITU_T4_1D;
-            break;
-        case '2':
-            compression = T4_COMPRESSION_ITU_T4_2D;
-            break;
-        case '6':
-            compression = T4_COMPRESSION_ITU_T6;
-            break;
         case 'i':
             photo_metric = PHOTOMETRIC_MINISBLACK;
             break;
@@ -637,7 +625,6 @@ int main(int argc, char *argv[])
         image_length = sequence[i].length;
         
         /* Write the image first.... */
-        row = 0;
         switch (sequence[i].type)
         {
         case 0:
diff --git a/libs/spandsp/tests/fax_tester.c b/libs/spandsp/tests/fax_tester.c
index 20af011981..544756f712 100644
--- a/libs/spandsp/tests/fax_tester.c
+++ b/libs/spandsp/tests/fax_tester.c
@@ -334,7 +334,7 @@ static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.17 (%.2fdBm0)\n", v17_rx_signal_power(&s->fast_modems.v17_rx));
-        s->rx_handler = (span_rx_handler_t *) &v17_rx;
+        s->rx_handler = (span_rx_handler_t) &v17_rx;
         s->rx_user_data = &s->fast_modems.v17_rx;
     }
     return 0;
@@ -355,7 +355,7 @@ static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.27ter (%.2fdBm0)\n", v27ter_rx_signal_power(&s->fast_modems.v27ter_rx));
-        s->rx_handler = (span_rx_handler_t *) &v27ter_rx;
+        s->rx_handler = (span_rx_handler_t) &v27ter_rx;
         s->rx_user_data = &s->fast_modems.v27ter_rx;
     }
     return 0;
@@ -376,7 +376,7 @@ static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
         /* The fast modem has trained, so we no longer need to run the slow
            one in parallel. */
         span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&s->fast_modems.v29_rx));
-        s->rx_handler = (span_rx_handler_t *) &v29_rx;
+        s->rx_handler = (span_rx_handler_t) &v29_rx;
         s->rx_user_data = &s->fast_modems.v29_rx;
     }
     return 0;
@@ -482,7 +482,7 @@ void faxtester_set_rx_type(void *user_data, int type, int bit_rate, int short_tr
                                     tone,
                                     tone_detected,
                                     (void *) s);
-        t->rx_handler = (span_rx_handler_t *) &modem_connect_tones_rx;
+        t->rx_handler = (span_rx_handler_t) &modem_connect_tones_rx;
         t->rx_user_data = &t->connect_rx;
         s->tone_state = MODEM_CONNECT_TONES_NONE;
         break;
@@ -491,31 +491,31 @@ void faxtester_set_rx_type(void *user_data, int type, int bit_rate, int short_tr
             s->flush_handler(s, s->flush_user_data, 3);
         fsk_rx_init(&t->v21_rx, &preset_fsk_specs[FSK_V21CH2], FSK_FRAME_MODE_SYNC, (put_bit_func_t) hdlc_rx_put_bit, put_bit_user_data);
         fsk_rx_signal_cutoff(&t->v21_rx, -45.5);
-        t->rx_handler = (span_rx_handler_t *) &fsk_rx;
+        t->rx_handler = (span_rx_handler_t) &fsk_rx;
         t->rx_user_data = &t->v21_rx;
         break;
     case T30_MODEM_V27TER:
         v27ter_rx_restart(&t->fast_modems.v27ter_rx, bit_rate, FALSE);
         v27ter_rx_set_put_bit(&t->fast_modems.v27ter_rx, put_bit_func, put_bit_user_data);
-        t->rx_handler = (span_rx_handler_t *) &v27ter_v21_rx;
+        t->rx_handler = (span_rx_handler_t) &v27ter_v21_rx;
         t->rx_user_data = s;
         break;
     case T30_MODEM_V29:
         v29_rx_restart(&t->fast_modems.v29_rx, bit_rate, FALSE);
         v29_rx_set_put_bit(&t->fast_modems.v29_rx, put_bit_func, put_bit_user_data);
-        t->rx_handler = (span_rx_handler_t *) &v29_v21_rx;
+        t->rx_handler = (span_rx_handler_t) &v29_v21_rx;
         t->rx_user_data = s;
         break;
     case T30_MODEM_V17:
         v17_rx_restart(&t->fast_modems.v17_rx, bit_rate, short_train);
         v17_rx_set_put_bit(&t->fast_modems.v17_rx, put_bit_func, put_bit_user_data);
-        t->rx_handler = (span_rx_handler_t *) &v17_v21_rx;
+        t->rx_handler = (span_rx_handler_t) &v17_v21_rx;
         t->rx_user_data = s;
         break;
     case T30_MODEM_DONE:
         span_log(&s->logging, SPAN_LOG_FLOW, "FAX exchange complete\n");
     default:
-        t->rx_handler = (span_rx_handler_t *) &span_dummy_rx;
+        t->rx_handler = (span_rx_handler_t) &span_dummy_rx;
         t->rx_user_data = s;
         break;
     }
@@ -549,7 +549,7 @@ void faxtester_set_tx_type(void *user_data, int type, int bit_rate, int short_tr
     {
     case T30_MODEM_PAUSE:
         silence_gen_alter(&t->silence_gen, ms_to_samples(short_train));
-        t->tx_handler = (span_tx_handler_t *) &silence_gen;
+        t->tx_handler = (span_tx_handler_t) &silence_gen;
         t->tx_user_data = &t->silence_gen;
         s->transmit = TRUE;
         break;
@@ -560,14 +560,14 @@ void faxtester_set_tx_type(void *user_data, int type, int bit_rate, int short_tr
         else
             tone = MODEM_CONNECT_TONES_FAX_CNG;
         modem_connect_tones_tx_init(&t->connect_tx, tone);
-        t->tx_handler = (span_tx_handler_t *) &modem_connect_tones_tx;
+        t->tx_handler = (span_tx_handler_t) &modem_connect_tones_tx;
         t->tx_user_data = &t->connect_tx;
         s->transmit = TRUE;
         break;
     case T30_MODEM_V21:
         fsk_tx_init(&t->v21_tx, &preset_fsk_specs[FSK_V21CH2], get_bit_func, get_bit_user_data);
         fsk_tx_set_modem_status_handler(&t->v21_tx, modem_tx_status, (void *) s);
-        t->tx_handler = (span_tx_handler_t *) &fsk_tx;
+        t->tx_handler = (span_tx_handler_t) &fsk_tx;
         t->tx_user_data = &t->v21_tx;
         s->transmit = TRUE;
         break;
@@ -575,7 +575,7 @@ void faxtester_set_tx_type(void *user_data, int type, int bit_rate, int short_tr
         v27ter_tx_restart(&t->fast_modems.v27ter_tx, bit_rate, t->use_tep);
         v27ter_tx_set_get_bit(&t->fast_modems.v27ter_tx, get_bit_func, get_bit_user_data);
         v27ter_tx_set_modem_status_handler(&t->fast_modems.v27ter_tx, modem_tx_status, (void *) s);
-        t->tx_handler = (span_tx_handler_t *) &v27ter_tx;
+        t->tx_handler = (span_tx_handler_t) &v27ter_tx;
         t->tx_user_data = &t->fast_modems.v27ter_tx;
         /* For any fast modem, set 200ms of preamble flags */
         hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
@@ -585,7 +585,7 @@ void faxtester_set_tx_type(void *user_data, int type, int bit_rate, int short_tr
         v29_tx_restart(&t->fast_modems.v29_tx, bit_rate, t->use_tep);
         v29_tx_set_get_bit(&t->fast_modems.v29_tx, get_bit_func, get_bit_user_data);
         v29_tx_set_modem_status_handler(&t->fast_modems.v29_tx, modem_tx_status, (void *) s);
-        t->tx_handler = (span_tx_handler_t *) &v29_tx;
+        t->tx_handler = (span_tx_handler_t) &v29_tx;
         t->tx_user_data = &t->fast_modems.v29_tx;
         /* For any fast modem, set 200ms of preamble flags */
         hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
@@ -595,7 +595,7 @@ void faxtester_set_tx_type(void *user_data, int type, int bit_rate, int short_tr
         v17_tx_restart(&t->fast_modems.v17_tx, bit_rate, t->use_tep, short_train);
         v17_tx_set_get_bit(&t->fast_modems.v17_tx, get_bit_func, get_bit_user_data);
         v17_tx_set_modem_status_handler(&t->fast_modems.v17_tx, modem_tx_status, (void *) s);
-        t->tx_handler = (span_tx_handler_t *) &v17_tx;
+        t->tx_handler = (span_tx_handler_t) &v17_tx;
         t->tx_user_data = &t->fast_modems.v17_tx;
         /* For any fast modem, set 200ms of preamble flags */
         hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
@@ -606,7 +606,7 @@ void faxtester_set_tx_type(void *user_data, int type, int bit_rate, int short_tr
         /* Fall through */
     default:
         silence_gen_alter(&t->silence_gen, 0);
-        t->tx_handler = (span_tx_handler_t *) &silence_gen;
+        t->tx_handler = (span_tx_handler_t) &silence_gen;
         t->tx_user_data = &t->silence_gen;
         s->transmit = FALSE;
         break;
@@ -636,21 +636,21 @@ void faxtester_set_tep_mode(faxtester_state_t *s, int use_tep)
 }
 /*- End of function --------------------------------------------------------*/
 
-void faxtester_set_real_time_frame_handler(faxtester_state_t *s, faxtester_real_time_frame_handler_t *handler, void *user_data)
+void faxtester_set_real_time_frame_handler(faxtester_state_t *s, faxtester_real_time_frame_handler_t handler, void *user_data)
 {
     s->real_time_frame_handler = handler;
     s->real_time_frame_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-void faxtester_set_front_end_step_complete_handler(faxtester_state_t *s, faxtester_front_end_step_complete_handler_t *handler, void *user_data)
+void faxtester_set_front_end_step_complete_handler(faxtester_state_t *s, faxtester_front_end_step_complete_handler_t handler, void *user_data)
 {
     s->front_end_step_complete_handler = handler;
     s->front_end_step_complete_user_data = user_data;
 }
 /*- End of function --------------------------------------------------------*/
 
-void faxtester_set_front_end_step_timeout_handler(faxtester_state_t *s, faxtester_front_end_step_complete_handler_t *handler, void *user_data)
+void faxtester_set_front_end_step_timeout_handler(faxtester_state_t *s, faxtester_front_end_step_complete_handler_t handler, void *user_data)
 {
     s->front_end_step_timeout_handler = handler;
     s->front_end_step_timeout_user_data = user_data;
@@ -686,9 +686,9 @@ static void faxtester_fax_modems_init(fax_modems_state_t *s, int use_tep, void *
     dc_restore_init(&s->dc_restore);
 
     s->rx_signal_present = FALSE;
-    s->rx_handler = (span_rx_handler_t *) &span_dummy_rx;
+    s->rx_handler = (span_rx_handler_t) &span_dummy_rx;
     s->rx_user_data = NULL;
-    s->tx_handler = (span_tx_handler_t *) &silence_gen;
+    s->tx_handler = (span_tx_handler_t) &silence_gen;
     s->tx_user_data = &s->silence_gen;
 }
 /*- End of function --------------------------------------------------------*/
@@ -725,7 +725,7 @@ int faxtester_free(faxtester_state_t *s)
 }
 /*- End of function --------------------------------------------------------*/
 
-void faxtester_set_flush_handler(faxtester_state_t *s, faxtester_flush_handler_t *handler, void *user_data)
+void faxtester_set_flush_handler(faxtester_state_t *s, faxtester_flush_handler_t handler, void *user_data)
 {
     s->flush_handler = handler;
     s->flush_user_data = user_data;
diff --git a/libs/spandsp/tests/t4_tests.c b/libs/spandsp/tests/t4_tests.c
index a2967948b7..fc8d3f4ebb 100644
--- a/libs/spandsp/tests/t4_tests.c
+++ b/libs/spandsp/tests/t4_tests.c
@@ -102,14 +102,12 @@ int rows_read = 0;
 
 static void dump_image_as_xxx(t4_state_t *state)
 {
-    uint8_t *s;
     int i;
     int j;
     int k;
 
     /* Dump the entire image as text 'X's and spaces */
     printf("Image (%d x %d):\n", receive_state.image_width, receive_state.image_length);
-    s = state->image_buffer;
     for (i = 0;  i < state->image_length;  i++)
     {
         for (j = 0;  j < state->bytes_per_row;  j++)
@@ -305,7 +303,7 @@ int main(int argc, char *argv[])
     int compression;
     int compression_step;
     int add_page_headers;
-    int overlay_page_headers;
+    //int overlay_page_headers;
     int min_row_bits;
     int restart_pages;
     int block_size;
@@ -329,7 +327,7 @@ int main(int argc, char *argv[])
     compression = -1;
     compression_step = 0;
     add_page_headers = FALSE;
-    overlay_page_headers = FALSE;
+    //overlay_page_headers = FALSE;
     restart_pages = FALSE;
     in_file_name = IN_FILE_NAME;
     decode_file_name = NULL;
@@ -395,11 +393,11 @@ int main(int argc, char *argv[])
             break;
         case 'h':
             add_page_headers = TRUE;
-            overlay_page_headers = FALSE;
+            //overlay_page_headers = FALSE;
             break;
         case 'H':
             add_page_headers = TRUE;
-            overlay_page_headers = TRUE;
+            //overlay_page_headers = TRUE;
             break;
         case 'r':
             restart_pages = TRUE;