perror()

Updated: October 26, 2022

Print an error message associated with errno

Synopsis:

#include <stdio.h>

void perror( const char *prefix );

Arguments:

prefix
NULL, or a string that you want to print before the error message.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The perror() function prints the following to stderr:

Examples:

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

int main( void )
  {
    FILE *fp;

    fp = fopen( "data.fil", "r" );
    if( fp == NULL ) {
      perror( "Unable to open file" );
      return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
  }

Classification:

ANSI, POSIX 1003.1

Safety:  
Cancellation point Yes
Interrupt handler No
Signal handler No
Thread Yes