---
name: "pthread_attr_setstack"
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_attr_setstack"
---

# pthread\_attr\_setstack(3)

set/get stack attributes in thread attributes object

## NAME

pthread\_attr\_setstack, pthread\_attr\_getstack - set/get stack attributes in thread attributes object

## LIBRARY

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

## SYNOPSIS

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

**int pthread\_attr\_setstack(**size\_t stacksize;                           **pthread\_attr\_t \****attr***,**                           **void** *stackaddr***\[***stacksize***\],**                           **size\_t** *stacksize***);** **int pthread\_attr\_getstack(const pthread\_attr\_t \*restrict** *attr***,**                           **void \*\*restrict** *stackaddr***,**                           **size\_t \*restrict** *stacksize***);**

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

**pthread\_attr\_getstack**(), **pthread\_attr\_setstack**():

```
    _POSIX_C_SOURCE >= 200112L
```

## DESCRIPTION

The **pthread\_attr\_setstack**() function sets the stack address and stack size attributes of the thread attributes object referred to by *attr* to the values specified in *stackaddr* and *stacksize*, respectively. These attributes specify the location and size of the stack that should be used by a thread that is created using the thread attributes object *attr*.

*stackaddr* should point to the lowest addressable byte of a buffer of *stacksize* bytes that was allocated by the caller. The pages of the allocated buffer should be both readable and writable.

The **pthread\_attr\_getstack**() function returns the stack address and stack size attributes of the thread attributes object referred to by *attr* in the buffers pointed to by *stackaddr* and *stacksize*, respectively.

## RETURN VALUE

On success, these functions return 0; on error, they return a nonzero error number.

## ERRORS

**pthread\_attr\_setstack**() can fail with the following error:

- **EINVAL**

  *stacksize* is less than **PTHREAD\_STACK\_MIN** (16384) bytes. On some systems, this error may also occur if *stackaddr* or *stackaddr + stacksize* is not suitably aligned.

POSIX.1 also documents an **EACCES** error if the stack area described by *stackaddr* and *stacksize* is not both readable and writable by the caller.

## ATTRIBUTES

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

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **pthread\_attr\_setstack**(), **pthread\_attr\_getstack**() | Thread safety | MT-Safe |

## STANDARDS

POSIX.1-2008.

## HISTORY

glibc 2.2. POSIX.1-2001.

## NOTES

These functions are provided for applications that must ensure that a thread's stack is placed in a particular location. For most applications, this is not necessary, and the use of these functions should be avoided. (Use [**pthread\_attr\_setstacksize**(3)](/pthread_attr_setstacksize/3.md) if an application simply requires a stack size other than the default.)

When an application employs **pthread\_attr\_setstack**(), it takes over the responsibility of allocating the stack. Any guard size value that was set using [**pthread\_attr\_setguardsize**(3)](/pthread_attr_setguardsize/3.md) is ignored. If deemed necessary, it is the application's responsibility to allocate a guard area (one or more pages protected against reading and writing) to handle the possibility of stack overflow.

The address specified in *stackaddr* should be suitably aligned: for full portability, align it on a page boundary (*sysconf(\_SC\_PAGESIZE)*). [**posix\_memalign**(3)](/posix_memalign/3.md) may be useful for allocation. Probably, *stacksize* should also be a multiple of the system page size.

If *attr* is used to create multiple threads, then the caller must change the stack address attribute between calls to [**pthread\_create**(3)](/pthread_create/3.md); otherwise, the threads will attempt to use the same memory area for their stacks, and chaos will ensue.

## EXAMPLES

See [**pthread\_attr\_init**(3)](/pthread_attr_init/3.md).

## SEE ALSO

[**mmap**(2)](/mmap/2.md), [**mprotect**(2)](/mprotect/2.md), [**posix\_memalign**(3)](/posix_memalign/3.md), [**pthread\_attr\_init**(3)](/pthread_attr_init/3.md), [**pthread\_attr\_setguardsize**(3)](/pthread_attr_setguardsize/3.md), [**pthread\_attr\_setstackaddr**(3)](/pthread_attr_setstackaddr/3.md), [**pthread\_attr\_setstacksize**(3)](/pthread_attr_setstacksize/3.md), [**pthread\_create**(3)](/pthread_create/3.md), [**pthreads**(7)](/pthreads/7.md)