Name
memchr, memrchr, rawmemchr - scan memory for a characterLibrary
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 ofc. 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).| Interface | Attribute | Value |
| T} | Thread safety | MT-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.