memchr(3) Library Functions Manual memchr(3)
NAME
memchr, memrchr, rawmemchr - scan memory for a character
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <string.h>
void *memchr(const void s[.n], int c, size_t n);
void *memrchr(const void s[.n], int c, size_t n);
[[deprecated]] void *rawmemchr(const void s[.n], int c);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
memrchr(), rawmemchr():
_GNU_SOURCE
DESCRIPTION
The 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.
The memrchr() function is like the memchr() function, except that it
searches backward from the end of the n bytes pointed to by s instead
of forward from the beginning.
The rawmemchr() function is similar to memchr(), but 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. If an in-
stance of c is not found, the behavior is undefined. Use either
strlen(3) or memchr(3) instead.
RETURN VALUE
The 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.
VERSIONS
rawmemchr() first appeared in glibc 2.1.
memrchr() first appeared in glibc 2.2.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│memchr(), memrchr(), rawmemchr() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
memchr(): POSIX.1-2001, POSIX.1-2008, 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.
SEE ALSO
bstring(3), ffs(3), memmem(3), strchr(3), strpbrk(3), strrchr(3),
strsep(3), strspn(3), strstr(3), wmemchr(3)
Linux man-pages 6.03 2023-01-05 memchr(3)
Generated by dwww version 1.15 on Fri Jun 21 14:01:41 CEST 2024.