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);

   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).

       ┌───────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │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)