strerror - Returns the error in C

#include <stdio.h>
#include <string.h>
#include <errno.h>

int main ()
{
  FILE * pFile;
  pFile = fopen ("unexist.ent","r");
  if (pFile == NULL)
    printf ("Error opening file unexist.ent: %s\n",strerror(errno));
  return 0;
}