diff --git a/example/hfp_ag_demo.c b/example/hfp_ag_demo.c
index 2bfc167f3..6ce600177 100644
--- a/example/hfp_ag_demo.c
+++ b/example/hfp_ag_demo.c
@@ -56,8 +56,10 @@
 #include <unistd.h>
 
 #include "btstack.h"
+#ifdef HAVE_STDIO
 #include "stdin_support.h"
- 
+#endif
+
 
 uint8_t hfp_service_buffer[150];
 const uint8_t    rfcomm_channel_nr = 1;
@@ -325,7 +327,7 @@ static void show_usage(void){
     printf("---\n");
 }
 
-static int stdin_process(struct data_source *ds){
+static void stdin_process(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type){
     read(ds->fd, &cmd, 1);
     switch (cmd){
         case 'a':
@@ -542,8 +544,6 @@ static int stdin_process(struct data_source *ds){
             show_usage();
             break;
     }
-
-    return 0;
 }
 #endif
 
diff --git a/example/hfp_hf_demo.c b/example/hfp_hf_demo.c
index e07477614..901eeab99 100644
--- a/example/hfp_hf_demo.c
+++ b/example/hfp_hf_demo.c
@@ -56,9 +56,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #include "btstack.h"
+#ifdef HAVE_STDIO
 #include "stdin_support.h"
+#endif
 
 uint8_t hfp_service_buffer[150];
 const uint8_t   rfcomm_channel_nr = 1;
@@ -161,13 +164,13 @@ static void show_usage(void){
     printf("---\n");
 }
 
-static int stdin_process(struct data_source *ds){
+static void stdin_process(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type){
     read(ds->fd, &cmd, 1);
 
     if (cmd >= '0' && cmd <= '9'){
         printf("DTMF Code: %c\n", cmd);
         hfp_hf_send_dtmf_code(device_addr, cmd);
-        return 0;
+        return;
     }
 
     switch (cmd){
@@ -438,8 +441,6 @@ static int stdin_process(struct data_source *ds){
             show_usage();
             break;
     }
-
-    return 0;
 }
 #endif
 
diff --git a/example/hsp_ag_demo.c b/example/hsp_ag_demo.c
index bb2be61be..4bc4c7438 100644
--- a/example/hsp_ag_demo.c
+++ b/example/hsp_ag_demo.c
@@ -59,6 +59,9 @@
 #include <unistd.h>
 
 #include "btstack.h"
+#ifdef HAVE_STDIO
+#include "stdin_support.h"
+#endif
 
 #define SCO_REPORT_PERIOD 255
 
@@ -130,7 +133,7 @@ static void show_usage(void){
 }
 
 #ifdef HAVE_STDIO
-static int stdin_process(struct data_source *ds){
+static void stdin_process(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type){
     char buffer;
     read(ds->fd, &buffer, 1);
 
@@ -184,7 +187,6 @@ static int stdin_process(struct data_source *ds){
             break;
 
     }
-    return 0;
 }
 #endif
 
diff --git a/example/hsp_hs_demo.c b/example/hsp_hs_demo.c
index d48d19cf6..53f0c369a 100644
--- a/example/hsp_hs_demo.c
+++ b/example/hsp_hs_demo.c
@@ -59,6 +59,9 @@
 #include <unistd.h>
 
 #include "btstack.h"
+#ifdef HAVE_STDIO
+#include "stdin_support.h"
+#endif
 
 #define SCO_REPORT_PERIOD 255
 
@@ -130,7 +133,7 @@ static void show_usage(void){
 }
 
 #ifdef HAVE_STDIO
-static int stdin_process(struct data_source *ds){
+static void stdin_process(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type){
     char buffer;
     read(ds->fd, &buffer, 1);
 
@@ -184,7 +187,6 @@ static int stdin_process(struct data_source *ds){
             show_usage();
             break;
     }
-    return 0;
 }
 #endif