---
name: "SDL_WaitSemaphore"
section: "3"
platform: "linux"
package: "libsdl3-doc"
version: "3.2.10+ds-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/SDL_WaitSemaphore"
---

# SDL\_WaitSemaphore(3)

Wait until a semaphore has a positive value and then decrements it.

## NAME

SDL\_WaitSemaphore - Wait until a semaphore has a positive value and then decrements it.

## HEADER FILE

Defined in SDL3/SDL\_mutex.h

## SYNOPSIS

```
#include "SDL3/SDL.h"
```

**void SDL\_WaitSemaphore(SDL\_Semaphore \*sem);**

## DESCRIPTION

This function suspends the calling thread until the semaphore pointed to by **sem** has a positive value, and then atomically decrement the semaphore value.

This function is the equivalent of calling

**SDL\_WaitSemaphoreTimeout** () with a time length of -1.

## FUNCTION PARAMETERS

- *sem*

  the semaphore wait on.

## AVAILABILITY

This function is available since SDL 3.2.0.

## SEE ALSO

**•**(3), [**SDL\_SignalSemaphore**(3)](/SDL_SignalSemaphore/3.md), **•**(3), [**SDL\_TryWaitSemaphore**(3)](/SDL_TryWaitSemaphore/3.md), **•**(3), [**SDL\_WaitSemaphoreTimeout**(3)](/SDL_WaitSemaphoreTimeout/3.md)