March 12, 2005 MEMMEM 3

### NAME

memmem - locate substring in byte string

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```void``*` memmem(```const void *block``, size_t blen``, const void *pat``, size_t plen`)

### DESCRIPTION

The memmem(``) function locates the first occurrence of the binary string ```pat` of size ```plen` bytes in the byte string ```block` of size ```blen` bytes.

### RETURN VALUES

The memmem(``) function returns a pointer to the substring located, or ```NULL` if no such substring exists within ```block`.

If ```plen` is zero, ```block` is returned, i.e. a zero length ```pat` is deemed to match the start of the string, as with strstr(3).

### SEE ALSO

bm(3), memchr(3), strchr(3), strstr(3)

### STANDARDS

The memmem(``) function is not currently standardized. However, it is meant to be API compatible with functions in FreeBSD and Linux.

### HISTORY

memmem(``) first appeared in the Free Software Foundation's glibc library.