MEMMEM(3) | Library Functions Manual | MEMMEM(3)

# NAME

`memmem` — locate a byte substring in a byte string

# SYNOPSIS

`#include <string.h>`

void *
`memmem`(const void *big, size_t big_len, const void *little, size_t little_len);

# DESCRIPTION

The `memmem`() function locates the first occurrence of the byte string little in the byte string big.

# RETURN VALUES

If little is zero length, big is returned; if little occurs nowhere in big, `NULL` is returned; otherwise a pointer to the first character of the first occurrence of little is returned.

# SEE ALSO

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

# STANDARDS

The `memmem`() function conforms to.

# HISTORY

The `memmem`() function first appeared in OpenBSD 5.4.

June 13, 2025 | Debian