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



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       strerror, strerror_r - get error message string

SYNOPSIS
       #include <string.h>

       char *strerror(int errnum);


       int strerror_r(int errnum, char *strerrbuf, size_t buflen);


DESCRIPTION
       For  strerror():    The  functionality  described on this reference page is aligned with the ISO C standard. Any conflict
       between the requirements described here and the ISO C standard is  unintentional.  This  volume  of  IEEE Std 1003.1-2001
       defers to the ISO C standard.

       The  strerror() function shall map the error number in errnum to a locale-dependent error message string and shall return
       a pointer to it. Typically, the values for errnum come from errno, but strerror() shall map any value of type  int  to  a
       message.

       The string pointed to shall not be modified by the application, but may be overwritten by a subsequent call to strerror()
        or perror().

       The contents of the error message strings returned by strerror() should be determined by the setting of  the  LC_MESSAGES
       category in the current locale.

       The implementation shall behave as if no function defined in this volume of IEEE Std 1003.1-2001 calls strerror().

       The strerror() function shall not change the setting of errno if successful.

       Since  no  return value is reserved to indicate an error, an application wishing to check for error situations should set
       errno to 0, then call strerror(), then check errno.

       The strerror() function need not be reentrant. A function that is not required to be reentrant  is  not  required  to  be
       thread-safe.

       The  strerror_r()  function  shall  map  the  error number in errnum to a locale-dependent error message string and shall
       return the string in the buffer pointed to by strerrbuf, with length buflen.

RETURN VALUE
       Upon successful completion, strerror() shall return a pointer to the generated message string. On error errno may be set,
       but no return value is reserved to indicate an error.

       Upon  successful  completion,  strerror_r()  shall return 0. Otherwise, an error number shall be returned to indicate the
       error.

ERRORS
       These functions may fail if:

       EINVAL The value of errnum is not a valid error number.


       The strerror_r() function may fail if:

       ERANGE Insufficient storage was supplied via strerrbuf and buflen to contain the generated message string.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       perror(), the Base Definitions volume of IEEE Std 1003.1-2001, <string.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, Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                  STRERROR(3P)