table of contents
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, int c);
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).
Interface | Attribute | Value |
memchr (), memrchr (), rawmemchr () | 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.
SEE ALSO¶
bstring(3), ffs(3), memmem(3), strchr(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3), wmemchr(3)
2024-05-02 | Linux man-pages 6.9.1 |