Check For The Missing Config File

 #include <stdio.h>  /* standard input/output routines. */

/* prepare "safe" hard-coded defaults */
/* for configurable parameters.       */
int config_use_colors = 0;
int config_memory_cache_size = 1024;

char* config_file_path = "....";
FILE* config_file = fopen(config_file_path, "r");

/* managed to open config file? - override hardcoded defaults. */
if (config_file) {
   /* check for config file's proper syntax, */
   /* and then use its contents. */
   .
   .
}
else {
   printf("Warning - cannot open configuration file '%s'. %s\n",
          config_file_path,
          "Check files existance and access permission.");
}