memchr, memrchr, rawmemchr - scan memory for a character

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ memchr(), memrchr(), rawmemchr()                                            │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

       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 unsignedchar.

       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.

memchr()
              POSIX.1-2001, C89, SVr4, 4.3BSD.

       memrchr()
              glibc 2.2.

       rawmemchr()
              glibc 2.1.

       Standard C library (libc, -lc)

       memchr, memrchr, rawmemchr - scan memory for a character

       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.

bstring(3),  ffs(3),  memmem(3),  strchr(3),  strpbrk(3),  strrchr(3),  strsep(3),  strspn(3), strstr(3),
       wmemchr(3)

Linux man-pages 6.9.1                              2024-05-02                                          memchr(3)

memchr()
              C11, POSIX.1-2008.

       memrchr()
       rawmemchr()
              GNU.

#include<string.h>void*memchr(constvoids[.n],intc,size_tn);void*memrchr(constvoids[.n],intc,size_tn);[[deprecated]]void*rawmemchr(constvoid*s,intc);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       memrchr(), rawmemchr():
           _GNU_SOURCE