---
name: "pthread_setugid_np"
section: "2"
platform: "macos"
package: "xnu"
version: "12377.121.6"
release: "macOS 26.5"
platforms: ["macos"]
url: "https://new.carta.tech/pthread_setugid_np"
---

# pthread\_setugid\_np(2)

Set the per-thread userid and single groupid.

## NAME

**pthread\_setugid\_np** – Set the per-thread userid and single groupid.

## SYNOPSIS

**#include \<sys/types.h\>**

**#include \<sys/unistd.h\>**

*int*\

**pthread\_setugid\_np**(*uid\_t uid, gid\_t gid*);

## DESCRIPTION

**pthread\_setugid\_np**() changes the current thread's effective, real, and saved userid and groupid to the requested userid and groupid ( *uid* and *gid* , respectively) and clears all other groupids.

*uid* can be the current real userid, KAUTH\_UID\_NONE, or, if the caller is privileged, any userid. *gid* can be the current real groupid or, if the caller is priviledged, any single groupid.

Setting *uid* to KAUTH\_UID\_NONE means to "revert to the per process credential".

## CAVEATS

Temporarily restoring root privileges for a non-privileged process is only possible on a per-process basis and not a per-thread basis.

**pthread\_setugid\_np**() is not intended as a privilege escalation mechanism.

Do not use **pthread\_setugid\_np.2**() in a security sensitive situation.

## RETURN VALUES

Upon successful completion, a value of 0 is returned. Otherwise, -1 is returned and the global variable *errno* is set to indicate the error.

## ERRORS

**pthread\_setugid\_np**() fails if one or more of the following are true:

- \[EPERM\]

  The calling process does not have the correct credentials to set the override identity (i.e. The current credentials do not imply "super-user").

- \[EPERM\]

  If *uid* is set to KAUTH\_UID\_NONE,  the current thread must already be assuming another identity in order to revert back.

- \[EPERM\]

  The current thread cannot already be assuming another identity.

## SEE ALSO

[setuid(2)](/setuid/2.md) [setgid(2)](/setgid/2.md) [seteuid(2)](/seteuid/2.md) [setegid(2)](/setegid/2.md)