.\"
.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for
.\" permission to reproduce portions of its copyrighted documentation.
.\" Original documentation from The Open Group can be obtained online at
.\" http://www.opengroup.org/bookstore/.
.\"
.\" The Institute of Electrical and Electronics Engineers and The Open
.\" Group, have given us permission to reprint portions of their
.\" documentation.
.\"
.\" In the following statement, the phrase ``this text'' refers to portions
.\" of the system documentation.
.\"
.\" Portions of this text are reprinted and reproduced in electronic form
.\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
.\" Standard for Information Technology -- Portable Operating System
.\" Interface (POSIX), The Open Group Base Specifications Issue 6,
.\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
.\" Engineers, Inc and The Open Group.  In the event of any discrepancy
.\" between these versions 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.
.\"
.\" This notice shall appear on any product containing this material.
.\"
.\" The contents of this file are subject to the terms of the
.\" Common Development and Distribution License (the "License").
.\" You may not use this file except in compliance with the License.
.\"
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
.\" or http://www.opensolaris.org/os/licensing.
.\" See the License for the specific language governing permissions
.\" and limitations under the License.
.\"
.\" When distributing Covered Code, include this CDDL HEADER in each
.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
.\" If applicable, add the following below this CDDL HEADER, with the
.\" fields enclosed by brackets "[]" replaced with your own identifying
.\" information: Portions Copyright [yyyy] [name of copyright owner]
.\"
.\"
.\" Copyright 1989 AT&T
.\" Copyright (c) 2001, The IEEE and The Open Group.  All Rights Reserved.
.\" Copyright (c) 2005, Sun Microsystems, Inc.  All Rights Reserved.
.\" Copyright 2015, Joyent, Inc.
.\"
.TH STRERROR 3C "Aug 17, 2015"
.SH NAME
strerror, strerror_r, strerror_l \- get error message string
.SH SYNOPSIS
.LP
.nf
#include <string.h>

\fBchar *\fR\fBstrerror\fR(\fBint\fR \fIerrnum\fR);
.fi

.LP
.nf
\fBint\fR \fBstrerror_r\fR(\fBint\fR \fIerrnum\fR, \fBchar *\fR\fIstrerrbuf\fR, \fBsize_t\fR  \fIbuflen\fR);
.fi

.LP
.nf
\fBchar *\fR\fBstrerror_l\fR(\fBint\fR \fIerrnum\fR, \fBlocale_t\fR \fIloc\fR);

.SH DESCRIPTION
.LP
The \fBstrerror()\fR function maps the error number in \fIerrnum\fR to an error
message string, and returns a pointer to that string. It uses the same set of
error messages as \fBperror\fR(3C). The returned string should not be
overwritten.
.sp
.LP
The \fBstrerror_r()\fR function maps the error number in \fIerrnum\fR to
an error message string and returns the string in the buffer pointed to by
\fIstrerrbuf\fR with length \fIbuflen\fR.
.sp
.LP
The \fBstrerror_l()\fR function maps the error number in \fIerrnum\fR to
an error message string in the locale indicated by \fIloc\fR.  The
returned string should not be overwritten. If \fIloc\fR is passed the
\fBNULL\fR pointer, then the locale of the calling thread's current locale
will be used instead.
.sp
.LP
Because the \fBstrerror()\fR and \fBstrerror_l()\fR functions, return localized
strings in the event of an unknown error, one must use the value of \fBerrno\fR
to detect an error. Callers should first set \fBerrno\fR to \fB0\fR before the
call to either function and then check the value of \fBerrno\fR after the call.
If the value of \fBerrno\fR is non-zero then an error has occurred.
.SH RETURN VALUES
.LP
Upon successful completion, \fBstrerror()\fR and \fBstrerror_l()\fR return a
pointer to the generated message string. Otherwise, they set \fBerrno\fR and
returns a pointer to an error message string. They return the localized string
"Unknown error" if \fIerrnum\fR is not a valid error number.
.sp
.LP
Upon successful completion, \fBstrerror_r()\fR returns 0.  Otherwise it sets
\fBerrno\fR and returns the value of \fBerrno\fR to indicate the error. It
returns the localized string "Unknown error" in the buffer pointed to by
\fIstrerrbuf\fR if \fIerrnum\fR is not a valid error number.
.SH ERRORS
.LP
These functions may fail if:
.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
The value of \fIerrnum\fR is not a valid error number.
.RE

.sp
.LP
The \fBstrerror_r()\fR function may fail if:
.sp
.ne 2
.na
\fB\fBERANGE\fR\fR
.ad
.RS 10n
The \fIbuflen\fR argument specifies insufficient storage to contain the
generated message string.
.RE

.SH USAGE
.LP
Messages returned from these functions are in the native language specified by
the \fBLC_MESSAGES\fR locale category. See \fBsetlocale\fR(3C) and
\fBuselocale\fR(3C).
.SH ATTRIBUTES
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	Safe
.TE

.SH SEE ALSO
.LP
\fBgettext\fR(3C), \fBperror\fR(3C), \fBsetlocale\fR(3C), \fBuselocale\fR(3C),
\fBattributes\fR(5), \fBstandards\fR(5)