---
name: "pthread_spin_init"
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_spin_destroy"
---

# pthread\_spin\_init(3)

initialize or destroy a spin lock

Part of [pthread\_spin\_destroy(3)](/pthread_spin_destroy/3.md).

## NAME

**pthread\_spin\_init**, **pthread\_spin\_destroy** – initialize or destroy a spin lock

## LIBRARY

POSIX Threads Library (libpthread, -lpthread)

## SYNOPSIS

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

*int*\

**pthread\_spin\_init**(*pthread\_spinlock\_t \*lock*, *int pshared*);

*int*\

**pthread\_spin\_destroy**(*pthread\_spinlock\_t \*lock*);

## DESCRIPTION

The **pthread\_spin\_init**() function will initialize *lock* to an unlocked state and allocate any resources necessary to begin using it. If *pshared* is set to PTHREAD\_PROCESS\_SHARED, any thread, whether belonging to the process in which the spinlock was created or not, that has access to the memory area where *lock* resides, can use *lock*. If it is set to PTHREAD\_PROCESS\_PRIVATE, it can only be used by threads within the same process.

The **pthread\_spin\_destroy**() function will destroy *lock* and release any resources that may have been allocated on its behalf.

## RETURN VALUES

If successful, both **pthread\_spin\_init**() and **pthread\_spin\_destroy**() will return zero. Otherwise, an error number will be returned to indicate the error.

Neither of these functions will return EINTR.

## ERRORS

The **pthread\_spin\_init**() and **pthread\_spin\_destroy**() functions will fail if:

- \[EBUSY\]

  An attempt to initialize or destroy *lock* while it is in use.

- \[EINVAL\]

  The value specified by *lock* is invalid.

The **pthread\_spin\_init**() function will fail if:

- \[EAGAIN\]

  Insufficient resources, other than memory, to initialize *lock*.

- \[ENOMEM\]

  Insufficient memory to initialize *lock*.

## SEE ALSO

[pthread\_spin\_lock(3)](/pthread_spin_lock/3.md), [pthread\_spin\_unlock(3)](/pthread_spin_unlock/3.md)

## HISTORY

The **pthread\_spin\_init**() and **pthread\_spin\_destroy**() functions first appeared in library “libkse” in FreeBSD 5.2, and in library “libthr” in FreeBSD 5.3. Support for process-shared spinlocks appeared in FreeBSD 11.0.