memchr - Man Page

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, 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 instance 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.

Attributes

For an explanation of the terms used in this section, see attributes(7).

InterfaceAttributeValue
memchr(), memrchr(), rawmemchr()Thread safetyMT-Safe

Standards

memchr()

C11, POSIX.1-2008.

memrchr()
rawmemchr()

GNU.

History

memchr()

POSIX.1-2001, C89, SVr4, 4.3BSD.

memrchr()

glibc 2.2.

rawmemchr()

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)

Referenced By

bstring(3), ffs(3), signal-safety(7), strchr(3), strnstr.3bsd(3), strpbrk(3), strsep(3), strspn(3), strstr(3), strtok(3), wmemchr(3).

The man pages memrchr(3) and rawmemchr(3) are aliases of memchr(3).

2023-10-31 Linux man-pages 6.06