NAME
memmem − locate a substring
SYNOPSIS
#include <string.h>
void *memmem(const void *haystack, size_t haystacklen,
const void *needle, size_t needlelen);
DESCRIPTION
The memmem() function finds the start of the first occurrence of the substring needle of length needlelen in the memory area haystack of length haystacklen.
RETURN VALUE
The memmem() function returns a pointer to the beginning of the substring, or NULL if the substring is not found.
CONFORMING TO
This function is a GNU extension.
BUGS
This function
was broken in Linux libraries up to and including libc
5.0.9; there the ’needle’ and
’haystack’ arguments were interchanged, and a
pointer to the end of the first occurrence of needle
was returned. Since libc 5.0.9 is still widely used, this is
a dangerous function to use.
Both old and new libc’s have the bug that if
needle is empty haystack-1 (instead of
haystack) is returned. And glibc (2.0.5) makes it
worse, and returns a pointer to the last byte of
’haystack’. Hopefully this will be fixed. For
the time being, memmem() should not be used with an
empty ’needle’.