memmem

MEMMEM(3)                  Linux Programmer's Manual                 MEMMEM(3)



NAME
       memmem - locate a substring

SYNOPSIS
       #define _GNU_SOURCE
       #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 sub-
       string, 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 makes it worse, and
       returns a pointer to the last byte of  `haystack'.  This  is  fixed  in
       glibc 2.1.

SEE ALSO
       strstr(3)



GNU                               1998-01-13                         MEMMEM(3)