---
name: "pthread_kill"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/pthread_kill/3"
---

# pthread\_kill(3)

send a signal to a specified thread

## NAME

**pthread\_kill** – send a signal to a specified thread

## LIBRARY

POSIX Threads Library (libpthread, -lpthread)

## SYNOPSIS

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

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

*int*\

**pthread\_kill**(*pthread\_t thread*, *int sig*);

## DESCRIPTION

The **pthread\_kill**() function sends a signal, specified by *sig*, to a thread, specified by *thread*. If *sig* is 0, error checking is performed, but no signal is actually sent.

## RETURN VALUES

If successful, **pthread\_kill**() returns 0. Otherwise, an error number is returned.

## ERRORS

The **pthread\_kill**() function will fail if:

- \[ESRCH\]

  *thread* is an invalid thread ID.

- \[EINVAL\]

  *sig* is an invalid or unsupported signal number.

## SEE ALSO

[kill(2)](/kill/2.md), [pthread\_self(3)](/pthread_self/3.md), [raise(3)](/raise/3.md)

## STANDARDS

The **pthread\_kill**() function conforms to ISO/IEC 9945-1:1996 (“POSIX.1”)