Closes #14

examples/include/util/output_handling.h

@@ -7,7 +7,7 @@ void print_midi_msg_buf(unsigned char * buf, long count) {
     }
     printf(" | ");
     for (byte_id = 0; byte_id < count; byte_id++) {
-        printf("%d ", buf[byte_id]);
+        printf("%03d ", buf[byte_id]);
     }
     printf("\n");
     fflush( stdout );

examples/input_bytes_callback/input.c

@@ -16,16 +16,28 @@ RMR_Port_config * port_config;
 MIDI_message * msg;
 error_message * err_msg;
 
+// Currently will be used for one integer value to show
+// how callback might interact with outside data.
+uint8_t * callback_values;
+
 void message_handler(
     double timestamp,
     unsigned char * buf,
     long count,
     void * user_data
 ) {
+    // Display a first value in "callback_values" contents
+    printf("%03d | ", ((uint8_t*)callback_values)[0]);
+    // Display MIDI message hex data
     print_midi_msg_buf(buf, count);
+    // Increment a first item in a pointer
+    ((uint8_t*)callback_values)[0]++;
 }
 
 int main() {
+    // Allocate a test variable to update periodically
+    callback_values = (uint8_t*) calloc(1, sizeof(uint8_t));
+
     // Allocate a MIDI_in_data instance, assign a
     // MIDI message queue and an error queue
     prepare_input_data_with_queues(&input_data);
@@ -76,6 +88,9 @@ int main() {
     // Destroy a port configuration
     destroy_port_config(port_config);
 
+    // Free pointer values
+    free(callback_values);
+
     // Exit without an error
     return 0;
 }

examples/virtual_input_callback/virtual_input.c

@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdint.h>
 #include <stdbool.h>
 // Keeps process running until Ctrl-C is pressed.
 // Contains a SIGINT handler and keep_process_running variable.
@@ -16,16 +17,28 @@ error_message * err_msg;
 
 RMR_Port_config * port_config;
 
+// Currently will be used for one integer value to show
+// how callback might interact with outside data.
+uint8_t * callback_values;
+
 void message_handler(
     double timestamp,
     unsigned char * buf,
     long count,
     void * user_data
 ) {
+    // Display a first value in "callback_values" contents
+    printf("%03d | ", ((uint8_t*)callback_values)[0]);
+    // Display MIDI message hex data
     print_midi_msg_buf(buf, count);
+    // Increment a first item in a pointer
+    ((uint8_t*)callback_values)[0]++;
 }
 
 int main() {
+    // Allocate a test variable to update periodically
+    callback_values = (uint8_t*) calloc(1, sizeof(uint8_t));
+
     // Allocate a MIDI_in_data instance, assign a
     // MIDI message queue and an error queue
     prepare_input_data_with_queues(&input_data);
@@ -42,7 +55,7 @@ int main() {
     open_virtual_port(data, "rmr", input_data);
 
     // Prepare to handle input through a callback
-    set_MIDI_in_callback(input_data, message_handler, NULL);
+    set_MIDI_in_callback(input_data, message_handler, callback_values);
 
     // Don't exit until Ctrl-C is pressed;
     // Look up "output_handling.h"
@@ -69,6 +82,9 @@ int main() {
     // Destroy a port configuration
     destroy_port_config(port_config);
 
+    // Free pointer values
+    free(callback_values);
+
     // Exit without an error
     return 0;
 }