---
name: "pthread_sigqueue"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/pthread_sigqueue"
---

# pthread\_sigqueue(3)

queue a signal and data to a thread

## NAME

pthread\_sigqueue - queue a signal and data to a thread

## LIBRARY

POSIX threads library (*libpthread*, *-lpthread*)

## SYNOPSIS

```
#include <signal.h>
#include <pthread.h>
```

**int pthread\_sigqueue(pthread\_t** *thread***, int** *sig***,**                      **const union sigval** *value***);**

Feature Test Macro Requirements for glibc (see [**feature\_test\_macros**(7)](/feature_test_macros/7.md)):

**pthread\_sigqueue**():

```
    _GNU_SOURCE
```

## DESCRIPTION

The **pthread\_sigqueue**() function performs a similar task to [**sigqueue**(3)](/sigqueue/3.md), but, rather than sending a signal to a process, it sends a signal to a thread in the same process as the calling thread.

The *thread* argument is the ID of a thread in the same process as the caller. The *sig* argument specifies the signal to be sent. The *value* argument specifies data to accompany the signal; see [**sigqueue**(3)](/sigqueue/3.md) for details.

## RETURN VALUE

On success, **pthread\_sigqueue**() returns 0; on error, it returns an error number.

## ERRORS

- **EAGAIN**

  The limit of signals which may be queued has been reached. (See [**signal**(7)](/signal/7.md) for further information.)

- **EINVAL**

  *sig* was invalid.

- **ENOSYS**

  **pthread\_sigqueue**() is not supported on this system.

- **ESRCH**

  *thread* is not valid.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **pthread\_sigqueue**() | Thread safety | MT-Safe |

## VERSIONS

The glibc implementation of **pthread\_sigqueue**() gives an error (**EINVAL**) on attempts to send either of the real-time signals used internally by the NPTL threading implementation. See [**nptl**(7)](/nptl/7.md) for details.

## STANDARDS

GNU.

## HISTORY

glibc 2.11.

## SEE ALSO

[**rt\_tgsigqueueinfo**(2)](/rt_tgsigqueueinfo/2.md), [**sigaction**(2)](/sigaction/2.md), [**pthread\_sigmask**(3)](/pthread_sigmask/3.md), [**sigqueue**(3)](/sigqueue/3.md), [**sigwait**(3)](/sigwait/3.md), [**pthreads**(7)](/pthreads/7.md), [**signal**(7)](/signal/7.md)