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PERROR(3P)                 POSIX Programmer's Manual                PERROR(3P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       perror - write error messages to standard error
SYNOPSIS
       #include <stdio.h>
       void perror(const char *s);

DESCRIPTION
       The perror() function shall map the error number accessed  through  the
       symbol  errno  to  a  language-dependent  error message, which shall be
       written to the standard error stream as follows:
        * First (if s is not a null pointer and the character pointed to by  s
          is  not  the  null  byte),  the string pointed to by s followed by a
          colon and a <space>.
        * Then an error message string followed by a <newline>.
       The contents of the error message strings shall be the  same  as  those
       returned by strerror() with argument errno.
       The  perror() function shall mark the file associated with the standard
       error stream as having been  written  (st_ctime,  st_mtime  marked  for
       update)  at  some  time  between  its successful completion and exit(),
       abort(), or the completion of fflush() or fclose() on stderr.
       The perror() function shall not change the orientation of the  standard
       error stream.
RETURN VALUE
       The perror() function shall not return a value.
ERRORS
       No errors are defined.
       The following sections are informative.
EXAMPLES
   Printing an Error Message for a Function
       The  following example replaces bufptr with a buffer that is the neces-
       sary size. If an error occurs, the perror() function prints  a  message
       and the program exits.

              #include <stdio.h>
              #include <stdlib.h>
              ...
              char *bufptr;
              size_t szbuf;
              ...
              if ((bufptr = malloc(szbuf)) == NULL) {
                  perror("malloc"); exit(2);
              }
              ...
APPLICATION USAGE
       None.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       strerror(),   the  Base  Definitions  volume  of  IEEE Std 1003.1-2001,
       <stdio.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                           PERROR(3P)