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memchr(3) Library Functions Manual memchr(3)
memchr, memrchr, rawmemchr - scan memory for a character
Standard C library (libc, -lc)
#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
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.
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.
For an explanation of the terms used in this section, see attributes(7). ┌─────────────────────────────────────┬───────────────┬─────────┐ │ Interface │ Attribute │ Value │ ├─────────────────────────────────────┼───────────────┼─────────┤ │ memchr(), memrchr(), rawmemchr() │ Thread safety │ MT-Safe │ └─────────────────────────────────────┴───────────────┴─────────┘
memchr() C11, POSIX.1-2008. memrchr() rawmemchr() GNU.
memchr() POSIX.1-2001, C89, SVr4, 4.3BSD. memrchr() glibc 2.2. rawmemchr() glibc 2.1.
bstring(3), ffs(3), memmem(3), strchr(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3), wmemchr(3)
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Linux man-pages 6.9.1 2024-05-02 memchr(3)
Pages that refer to this page: bstring(3), ffs(3), memchr(3), strchr(3), strpbrk(3), strsep(3), strspn(3), strstr(3), strtok(3), wmemchr(3), signal-safety(7)