---
name: "pthread_rwlockattr_setpshared"
section: "3"
platform: "macos"
package: "libpthread"
version: "539.100.4"
release: "macOS 26.5"
platforms: ["freebsd", "macos"]
url: "https://new.carta.tech/pthread_rwlockattr_setpshared"
---

# pthread\_rwlockattr\_setpshared(3)

set the process shared attribute

## NAME

**pthread\_rwlockattr\_setpshared** – set the process shared attribute

## SYNOPSIS

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

*int*\

**pthread\_rwlockattr\_setpshared**(*pthread\_rwlockattr\_t \*attr*, *int pshared*);

## DESCRIPTION

The **pthread\_rwlockattr\_setpshared**() function sets the process shared attribute of *attr* to the value referenced by *pshared*. The *pshared* argument may be one of two values:

- PTHREAD\_PROCESS\_SHARED

  Any thread of any process that has access to the memory where the read/write lock resides can manipulate the lock.

- PTHREAD\_PROCESS\_PRIVATE

  Only threads created within the same process as the thread that initialized the read/write lock can manipulate the lock. This is the default value.

## RETURN VALUES

If successful, the **pthread\_rwlockattr\_setpshared**() function will return zero. Otherwise an error number will be returned to indicate the error.

## ERRORS

The **pthread\_rwlockattr\_setpshared**() function will fail if:

- \[EINVAL\]

  The value specified by *attr* or *pshared* is invalid.

## SEE ALSO

[pthread\_rwlock\_init(3)](/pthread_rwlock_init/3.md), [pthread\_rwlockattr\_getpshared(3)](/pthread_rwlockattr_getpshared/3.md), [pthread\_rwlockattr\_init(3)](/pthread_rwlockattr_init/3.md)

## STANDARDS

The **pthread\_rwlockattr\_setpshared**() function is expected to conform to Version 2 of the Single UNIX Specification (“SUSv2”).

## HISTORY

The **pthread\_rwlockattr\_setpshared**() function first appeared in FreeBSD 3.0.

## BUGS

The PTHREAD\_PROCESS\_SHARED attribute is not supported.