Copyright 1993 David Metcalfe (email@example.com) and Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk <firstname.lastname@example.org> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulti...
NAMEmemchr, memrchr, rawmemchr - scan memory for a character
#include <string.h> void *memchr(const void *s, int c, size_t n); void *memrchr(const void *s, int c, size_t n); void *rawmemchr(const void *s, int c);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
memrchr(), rawmemchr(): _GNU_SOURCE
DESCRIPTIONThe memchr() function scans the initial n bytes of the memory area pointed to by s for the first instance of c. Both c and the bytes of the memory area pointed to by s are interpreted as unsigned char.
function is like the
except that it searches backward from the end of the
bytes pointed to by
instead of forward from the beginning.
The rawmemchr() function is similar to memchr(): it assumes (i.e., the programmer knows for certain) that an instance of c lies somewhere in the memory area starting at the location pointed to by s, and so performs an optimized search for c (i.e., no use of a count argument to limit the range of the search). If an instance of c is not found, the results are unpredictable. The following call is a fast means of locating a string's terminating null byte:
char *p = rawmemchr(s, aq\0aq);
RETURN VALUEThe memchr() and memrchr() functions return a pointer to the matching byte or NULL if the character does not occur in the given memory area.
The rawmemchr() function returns a pointer to the matching byte, if one is found. If no matching byte is found, the result is unspecified.
VERSIONSrawmemchr() first appeared in glibc in version 2.1.
memrchr() first appeared in glibc in version 2.2.
ATTRIBUTESFor an explanation of the terms used in this section, see attributes(7).
|memchr(), memrchr(), rawmemchr()||Thread safety||MT-Safe|
CONFORMING TOmemchr(): POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD.
The memrchr() function is a GNU extension, available since glibc 2.1.91.
The rawmemchr() function is a GNU extension, available since glibc 2.1.