perror()
QNX SDP8.0C Library ReferenceAPIDeveloper
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:
- the given prefix, followed by 
: - the error message returned by strerror() for the current value of errno
 - a newline character.
 
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:
| Safety: | |
|---|---|
| Cancellation point | Yes | 
| Signal handler | No | 
| Thread | Yes | 
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