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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 (consult 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 vol-
       ume of IEEE Std 1003.1-2001 calls strerror().
       The strerror() function shall not change the setting of errno  if  suc-
       cessful.
       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, 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                         STRERROR(3P)