memmem(3)		    Library Functions Manual		       memmem(3)

NAME
     memmem - locate a substring

LIBRARY
     Standard C library (libc, -lc)

SYNOPSIS
     #define _GNU_SOURCE	 /* See feature_test_macros(7) */
     #include <string.h>

     void *memmem(size_t hsize, size_t nsize;
		  const void haystack[hsize], size_t hsize,
		  const void needle[nsize], size_t nsize);

DESCRIPTION
     The  memmem()  function finds the start of the first occurrence of the sub-
     string needle of size nsize in the memory area haystack of size hsize.

RETURN VALUE
     The memmem() function returns a pointer to the beginning of the  substring,
     or NULL if the substring is not found.

ATTRIBUTES
     For  an  explanation  of the terms used in this section, see attributes(7).
     allbox; lbx lb lb l l l.  Interface Attribute Value T{ memmem() T}	  Thread
     safety  MT-Safe

STANDARDS
     None.

HISTORY
     musl libc 0.9.7; FreeBSD 6.0, OpenBSD 5.4, NetBSD, Illumos.

BUGS
     In glibc 2.0, if needle is empty, memmem() returns a pointer  to  the  last
     byte of haystack.	This is fixed in glibc 2.1.

SEE ALSO
     bstring(3), strstr(3)

Linux man-pages 6.18		   2026-02-08			       memmem(3)