Check Access Permissions (continued.)

 #include <stdio.h>   /* standard input/output routines. */
 #include <unistd.h>  /* access(), R_OK etc.             */
 #include <string.h>  /* strchr(), etc.                  */
 #include <malloc.h>  /* malloc(), etc.                  */

/*
 * function: check_Access. 
 * input:    full path to a file, and pointer to error string.
 * output:   '1' if permission is granted, or '0' and a
 *           detailed explanation if some problem was found.
 */
int
check_access(char* file_path, char** error_msg)
{
  char* dir_path;        /* full path to a directory.        */
  char* p_slash;         /* location of next '/' in path.    */
  static char err_msg[1024];
                         /* static memory for error message. */

  /* prepare for returning error message. */
  *error_msg = err_msg;

  dir_path = (char*)malloc(strlen(file_path)+1);
  if (!dir_path) {
    sprintf(err_msg, "out of memory");
    return 0;
  }