---
name: "sigwait"
section: "2"
platform: "macos"
package: "Libc"
version: "1752.120.2"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/sigwait"
---

# sigwait(2)

select a set of signals

## NAME

**sigwait** – select a set of signals

## SYNOPSIS

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

*int*\

**sigwait**(*const sigset\_t \*restrict set*, *int \*restrict sig*);

## DESCRIPTION

The **sigwait**() function selects a set of signals, specified by *set*. If none of the selected signals are pending, **sigwait**() waits until one or more of the selected signals has been generated. Then **sigwait**() atomically clears one of the selected signals from the set of pending signals for the process and sets the location pointed to by *sig* to the signal number that was cleared.

The signals specified by *set* should be blocked, but not ignored, at the time of the call to **sigwait**().

Processes which call  **sigwait**() on ignored signals will wait indefinitely.  Ignored  signals are dropped immediately by the system, before delivery  to a waiting process.

## RETURN VALUES

If successful, **sigwait**() returns 0 and sets the location pointed to by *sig* to the cleared signal number. Otherwise, an error number is returned.

## ERRORS

**sigwait**() will fail if:

- \[EINVAL\]

  *set* specifies one or more invalid signal numbers.

## SEE ALSO

[pthread\_sigmask(2)](/pthread_sigmask/2.md), [sigaction(2)](/sigaction/2.md), [sigpending(2)](/sigpending/2.md), [sigsuspend(2)](/sigsuspend/2.md), [pause(3)](/pause/3.md)

## STANDARDS

**sigwait**() conforms to ISO/IEC 9945-1:1996 (\`\`POSIX.1'')