Automated addition of parentheses by add_parens_for_own_funcs.sh

[thirdparty/man-pages.git] / man3 / strerror.3

.\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk)
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.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Sat Jul 24 18:05:30 1993 by Rik Faith <faith@cs.unc.edu>
.\" Modified Fri Feb 16 14:25:17 1996 by Andries Brouwer <aeb@cwi.nl>
.\" Modified Sun Jul 21 20:55:44 1996 by Andries Brouwer <aeb@cwi.nl>
.\" Modified Mon Oct 15 21:16:25 2001 by John Levon <moz@compsoc.man.ac.uk>
.\" Modified Tue Oct 16 00:04:43 2001 by Andries Brouwer <aeb@cwi.nl>
.\" Modified Fri Jun 20 03:04:30 2003 by Andries Brouwer <aeb@cwi.nl>
.\"
.TH STRERROR 3  2001-10-16 "" "Linux Programmer's Manual"
.SH NAME
strerror, strerror_r \- return string describing error code
.SH SYNOPSIS
.nf
.B #include <string.h>
.sp
.BI "char *strerror(int " errnum );
.sp
.B #define _XOPEN_SOURCE 600
.B #include <string.h>
.sp
.BI "int strerror_r(int " errnum ", char *" buf ", size_t " n );
.fi
.SH DESCRIPTION
The \fBstrerror()\fP function returns a string describing the error
code passed in the argument \fIerrnum\fP, 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 subsequent call to \fBperror()\fP or \fBstrerror()\fP.
No library function will modify this string.

The \fBstrerror_r()\fP function is similar to \fBstrerror()\fP, but is
thread safe. It returns the string in the user-supplied buffer
.I buf
of length
.IR n .

.SH "RETURN VALUE"
The \fBstrerror()\fP function returns the appropriate error description
string, or an unknown error message if the error code is unknown.
The value of \fIerrno\fP is not changed for a successful call, and is
set to a non-zero value upon error.
The \fBstrerror_r()\fP function returns 0 on success and \-1 on failure,
setting \fIerrno\fP.

.SH ERRORS
.TP
.B EINVAL
The value of
.I errnum
is not a valid error number.
.TP
.B ERANGE
Insufficient storage was supplied to contain the error description string.

.SH "CONFORMING TO"
SVID 3, POSIX, 4.3BSD, ISO/IEC 9899:1990 (C89).
.br
.BR 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
.sp
.BI "char *strerror_r(int " errnum ", char *" buf ", size_t " n );
.sp
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-terminated.
.SH "SEE ALSO"
.BR errno (3),
.BR perror (3),
.BR strsignal (3)