redhat man page for strerror

STRERROR(3)						     Linux Programmer's Manual						       STRERROR(3)

NAME
       strerror, strerror_r - return string describing error code

SYNOPSIS
       #include <string.h>

       char *strerror(int errnum);
       int strerror_r(int errnum, char *buf, size_t n);

DESCRIPTION
       The  strerror()	function  returns a string describing the error code passed in the argument errnum, possibly using the LC_MESSAGES part of
       the current locale to select the appropriate language.  This string must not be modified by the application, but may be modified by a  sub-
       sequent call to perror() or strerror().	No library function will modify this string.

       The strerror_r() function is similar to strerror(), but is thread safe. It returns the string in the user-supplied buffer buf of length n.

RETURN VALUE
       The  strerror()	function  returns the appropriate error description string, or an unknown error message if the error code is unknown.  The
       value of errno is not changed for a successful call, and is set to a nonzero value upon error.  The strerror_r() function returns 0 on suc-
       cess and -1 on failure, setting errno.

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

       ERANGE Insufficient storage was supplied to contain the error description string.

CONFORMING TO
       SVID 3, POSIX, BSD 4.3, ISO/IEC 9899:1990 (C89).
       strerror_r()  with prototype as given above is specified by SUSv3, and was in use under Digital Unix and HP Unix. An incompatible function,
       with prototype

       char *strerror_r(int errnum, char *buf, size_t n);

       is a GNU extension used by glibc (since 2.0), and must be regarded as obsolete in view of SUSv3.  The GNU version may, but  need  not,  use
       the  user-supplied buffer.  If it does, the result may be truncated in case the supplied buffer is too small. The result is always NUL-ter-
       minated.

SEE ALSO
       errno(3), perror(3), strsignal(3)

								    2001-10-16							       STRERROR(3)