---
name: "SDL_HINT_THREAD_FORCE_REALTIME_TIME_CRITICAL"
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_HINT_THREAD_FORCE_REALTIME_TIME_CRITICAL"
---

# SDL\_HINT\_THREAD\_FORCE\_REALTIME\_TIME\_CRITICAL(3)

Specifies whether SDL\_THREAD\_PRIORITY\_TIME\_CRITICAL should be treated as realtime.

## NAME

SDL\_HINT\_THREAD\_FORCE\_REALTIME\_TIME\_CRITICAL - Specifies whether  **SDL\_THREAD\_PRIORITY\_TIME\_CRITICAL**\
  should be treated as realtime.

## HEADER FILE

Defined in SDL3/SDL\_hints.h

## SYNOPSIS

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

**#define SDL\_HINT\_THREAD\_FORCE\_REALTIME\_TIME\_CRITICAL** *SDL\_THREAD\_FORCE\_REALTIME\_TIME\_CRITICAL"*

## DESCRIPTION

On some platforms, like Linux, a realtime priority thread may be subject to restrictions that require special handling by the application. This hint exists to let SDL know that the app is prepared to handle said restrictions.

On Linux, SDL will apply the following configuration to any thread that becomes realtime:

• The SCHED\_RESET\_ON\_FORK bit will be set on the scheduling policy,

• An RLIMIT\_RTTIME budget will be configured to the rtkit specified limit.

• Exceeding this limit will result in the kernel sending SIGKILL to the\
   app, refer to the man pages for more information.

The variable can be set to the following values:

• "0": default platform specific behaviour

• "1": Force

**SDL\_THREAD\_PRIORITY\_TIME\_CRITICAL**\
  to\
   a realtime scheduling policy

This hint should be set before calling

**SDL\_SetCurrentThreadPriority** ()

## AVAILABILITY

This hint is available since SDL 3.2.0.