1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" %%%LICENSE_START(VERBATIM)
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
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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14 .\" manual page may be incorrect or out-of-date.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.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
29 .\" Modified Sat Jul 24 17:56:43 1993 by Rik Faith (faith@cs.unc.edu)
30 .\" Added history, aeb, 980113.
31 .\" 2005-05-05 mtk: added strcasestr()
33 .TH STRSTR 3 2014-08-19 "GNU" "Linux Programmer's Manual"
35 strstr, strcasestr \- locate a substring
38 .B #include <string.h>
40 .BI "char *strstr(const char *" haystack ", const char *" needle );
42 .BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
44 .B #include <string.h>
46 .BI "char *strcasestr(const char *" haystack ", const char *" needle );
51 function finds the first occurrence of the substring
55 The terminating null bytes (\(aq\\0\(aq) are not compared.
61 but ignores the case of both arguments.
63 These functions return a pointer to the beginning of the
64 located substring, or NULL if the substring is not found.
66 .SS Multithreading (see pthreads(7))
69 function is thread-safe.
73 function is thread-safe with exceptions.
74 It can be safely used in multithreaded applications, as long as
76 is not called to change the locale during its execution.
80 function conforms to C89 and C99.
83 function is a nonstandard extension.
85 .\" Early versions of Linux libc (like 4.5.26) would not allow
90 .\" Later versions (like 4.6.27) work correctly,