perror [C++ Reference]
Keywords: c,io,perror
Date: 2009-09-02T19:16:37-0700

## perror

Syntax:

        #include <cstdio>
        void perror( const char *str );

The perror() function prints str and an implementation-defined error message corresponding to the global variable errno. For example:

        char* input_filename = "not_found.txt";
        FILE* input = fopen( input_filename, "r" );
        if( input == NULL ) {
          char error_msg[255];
          sprintf( error_msg, "Error opening file '%s'", input_filename );
          perror( error_msg );
          exit( -1 );
        }

If the file called not_found.txt is not found, this code will produce the following output:

        Error opening file 'not_found.txt': No such file or directory

Related Topics: clearerr, feof, ferror, strerror