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, 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 .