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

# bcmp(3)

compare byte string

## NAME

**bcmp** – compare byte string

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

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

*int*\

**bcmp**(*const void \*b1*, *const void \*b2*, *size\_t len*);

## DESCRIPTION

The **bcmp**() function compares byte string *b1* against byte string *b2*, returning zero if they are identical, non-zero otherwise. Both strings are assumed to be *len* bytes long. Zero-length strings are always identical.

The strings may overlap.

## SEE ALSO

[memcmp(3)](/memcmp/3.md), [strcasecmp(3)](/strcasecmp/3.md), [strcmp(3)](/strcmp/3.md), [strcoll(3)](/strcoll/3.md), [strxfrm(3)](/strxfrm/3.md), [timingsafe\_bcmp(3)](/timingsafe_bcmp/3.md)

## HISTORY

A **bcmp**() function first appeared in 4.2BSD. Its prototype existed previously in ⟨string.h⟩ before it was moved to ⟨strings.h⟩ for IEEE Std 1003.1-2001 (“POSIX.1”) compliance.