#include <aubio.h>#include <stdio.h>#include "aubio_priv.h" const char_t *hdr = "CUSTOM HEADER: ";const char_t *hdr2 = "OTHER HEADER: "; /* an example of logging function that adds a custom header and prints * aubio debug messages on stdout instead of stderr */void logging(int level, const char_t *message, void *data) {  FILE *out;  //fprintf(stdout, "using custom logging function\n");  if (level == AUBIO_LOG_ERR) {    out = stderr;  } else {    out = stdout;  }  if ((level >= 0) && (data != NULL)) {    fprintf(out, "%s", (const char_t *)data);  }  fprintf(out, "%s", message);} int main (void){  fprintf(stdout, "### testing normal logging\n");  AUBIO_ERR("testing normal AUBIO_LOG_ERR\n");  AUBIO_INF("testing normal AUBIO_LOG_INF\n");  AUBIO_WRN("testing normal AUBIO_LOG_WRN\n");  AUBIO_MSG("testing normal AUBIO_LOG_MSG\n");  AUBIO_DBG("testing normal AUBIO_LOG_DBG\n");   fprintf(stdout, "### testing with one custom function\n");  aubio_log_set_function(logging, (void *)hdr);  AUBIO_ERR("testing custom set_function AUBIO_LOG_ERR\n");  AUBIO_INF("testing custom set_function AUBIO_LOG_INF\n");  AUBIO_WRN("testing custom set_function AUBIO_LOG_WRN\n");  AUBIO_MSG("testing custom set_function AUBIO_LOG_MSG\n");  AUBIO_DBG("testing custom set_function AUBIO_LOG_DBG\n");   fprintf(stdout, "### testing resetted logging\n");  aubio_log_reset();  AUBIO_ERR("testing again normal AUBIO_LOG_ERR\n");  AUBIO_INF("testing again normal AUBIO_LOG_INF\n");  AUBIO_WRN("testing again normal AUBIO_LOG_WRN\n");  AUBIO_MSG("testing again normal AUBIO_LOG_MSG\n");  AUBIO_DBG("testing again normal AUBIO_LOG_DBG\n");   fprintf(stdout, "### testing per level customization\n");  aubio_log_set_level_function(AUBIO_LOG_ERR, logging, (void *)hdr2);  aubio_log_set_level_function(AUBIO_LOG_WRN, logging, NULL);  aubio_log_set_level_function(AUBIO_LOG_MSG, logging, (void *)hdr);  AUBIO_ERR("testing custom set_level_function AUBIO_LOG_ERR\n");  AUBIO_INF("testing again normal AUBIO_LOG_INF\n");  AUBIO_WRN("testing custom set_level_function AUBIO_LOG_WRN with data=NULL\n");  AUBIO_MSG("testing custom set_level_function AUBIO_LOG_MSG\n");  AUBIO_DBG("testing again normal AUBIO_LOG_DBG\n");   return 0;}