---
name: "lsearch"
section: "3"
platform: "macos"
package: "Libc"
version: "1752.120.2"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/lsearch"
---

# lsearch(3)

linear search and append

## NAME

**lfind**, **lsearch** – linear search and append

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<search.h\>**

*void \**\

**lfind**(*const void \*key*, *const void \*base*, *size\_t \*nelp*, *size\_t width*, *int \*comparconst void \*, const void \**);

*void \**\

**lsearch**(*const void \*key*, *void \*base*, *size\_t \*nelp*, *size\_t width*, *int \*comparconst void \*, const void \**);

## DESCRIPTION

The **lsearch**() and **lfind**() functions walk linearly through an array, comparing each element with the one to be sought, by means of a supplied comparison function.

The *key* argument points to an element that matches the one that is searched. The array's address in memory is denoted by the *base* argument. The width of one element (i.e., the size as returned by **sizeof**()) is passed as the *width* argument. The number of valid elements contained in the array (not the number of elements the array has space reserved for) is given in the integer pointed to by *nelp*. The *compar* argument points to a function which compares its two arguments and returns zero if they are matching, and non-zero otherwise.

If no matching element was found in the array, **lsearch**() copies *key* into the position after the last element and increments the integer pointed to by *nelp*.

## RETURN VALUES

The **lsearch**() and **lfind**() functions return a pointer to the first element found. If no element was found, **lsearch**() returns a pointer to the newly added element, whereas **lfind**() returns NULL. Both functions return NULL if an error occurs.

## SEE ALSO

[bsearch(3)](/bsearch/3.md), [hsearch(3)](/hsearch/3.md), [tsearch(3)](/tsearch/3.md)

## STANDARDS

The **lsearch**() and **lfind**() functions conform to IEEE Std 1003.1-2001 (“POSIX.1”).

## HISTORY

The **lsearch**() and **lfind**() functions appeared in 4.2BSD. In FreeBSD 5.0, they reappeared conforming to IEEE Std 1003.1-2001 (“POSIX.1”).