1 .\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk)
2 .\" and Copyright (C) 2005, Michael Kerrisk <mtk.manpages@gmail.com>
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
6 .\" preserved on all copies.
8 .\" Permission is granted to copy and distribute modified versions of this
9 .\" manual under the conditions for verbatim copying, provided that the
10 .\" entire resulting derived work is distributed under the terms of a
11 .\" permission notice identical to this one.
13 .\" Since the Linux kernel and libraries are constantly changing, this
14 .\" manual page may be incorrect or out-of-date. The author(s) assume no
15 .\" responsibility for errors or omissions, or for damages resulting from
16 .\" the use of the information contained herein. The author(s) may not
17 .\" have taken the same level of care in the production of this manual,
18 .\" which is licensed free of charge, as they might when working
21 .\" Formatted or processed versions of this manual, if unaccompanied by
22 .\" the source, must acknowledge the copyright and authors of this work.
24 .\" References consulted:
25 .\" Linux libc source code
26 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
28 .\" Modified Sat Jul 24 18:05:30 1993 by Rik Faith <faith@cs.unc.edu>
29 .\" Modified Fri Feb 16 14:25:17 1996 by Andries Brouwer <aeb@cwi.nl>
30 .\" Modified Sun Jul 21 20:55:44 1996 by Andries Brouwer <aeb@cwi.nl>
31 .\" Modified Mon Oct 15 21:16:25 2001 by John Levon <moz@compsoc.man.ac.uk>
32 .\" Modified Tue Oct 16 00:04:43 2001 by Andries Brouwer <aeb@cwi.nl>
33 .\" Modified Fri Jun 20 03:04:30 2003 by Andries Brouwer <aeb@cwi.nl>
34 .\" 2005-12-13, mtk, Substantial rewrite of strerror_r() description
35 .\" Addition of extra material on portability and standards.
37 .TH STRERROR 3 2009-03-30 "" "Linux Programmer's Manual"
39 strerror, strerror_r \- return string describing error number
42 .B #include <string.h>
44 .BI "char *strerror(int " errnum );
46 .BI "int strerror_r(int " errnum ", char *" buf ", size_t " buflen );
49 .BI "char *strerror_r(int " errnum ", char *" buf ", size_t " buflen );
54 Feature Test Macro Requirements for glibc (see
55 .BR feature_test_macros (7)):
58 The XSI-compliant version of
62 (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !\ _GNU_SOURCE
64 Otherwise, the GNU-specific version is provided.
68 function returns a pointer to a string that describes the error
69 code passed in the argument \fIerrnum\fP, possibly using the
71 part of the current locale to select the appropriate language.
72 This string must not be modified by the application, but may be
73 modified by a subsequent call to
77 No library function will modify this string.
81 function is similar to
85 This function is available in two versions:
86 an XSI-compliant version specified in POSIX.1-2001
87 (available since glibc 2.3.4),
88 and a GNU-specific version (available since glibc 2.0).
89 The XSI-compliant version is provided with the feature test macros
90 settings shown in the SYNOPSIS;
91 otherwise the GNU-specific version is provided.
92 If no feature test macros are explicitly defined,
93 then (since glibc 2.4)
95 is defined by default with the value
96 200112L, so that the XSI-compliant version of
98 is provided by default.
102 is preferred for portable applications.
103 It returns the error string in the user-supplied buffer
110 returns a pointer to a string containing the error message.
111 This may be either a pointer to a string that the function stores in
113 or a pointer to some (immutable) static string
117 If the function stores a string in
121 bytes are stored (the string may be truncated if
123 is too small) and the string always includes a terminating null byte.
130 the appropriate error description string,
131 or an "Unknown error nnn" message if the error number is unknown.
135 function returns 0 on success;
136 on error, \-1 is returned and
138 is set to indicate the error.
144 is not a valid error number.
147 Insufficient storage was supplied to contain the error description string.
150 is specified by POSIX.1-2001, C89, C99.
152 is specified by POSIX.1-2001.
156 function is a nonstandard extension.
162 if the call encounters an error, but does not specify what
163 value should be returned as the function result in the event of an error.
165 .\" e.g., Solaris 8, HP-UX 11
167 returns NULL if the error number is unknown.
169 .\" e.g., FreeBSD 5.4, Tru64 5.1B
171 returns a string something like "Error nnn occurred" and sets
175 if the error number is unknown.