// perror example
// source: http://www.cplusplus.com/  

#include <stdio.h>
#include <stdlib.h>

int main()
{
  FILE * pFile;
  pFile=fopen("nonexistentfile.txt","r");
  if (pFile == NULL) {
    perror("The following error occurred");
    return EXIT_FAILURE;
  } else {
    fclose(pFile);
  }
  return EXIT_SUCCESS;
}