====== (This is the legacy documentation for stable SDL2, the current stable version; [https://wiki.libsdl.org/SDL3/ SDL3] is the current development version.) ======
= SDL_WaitThread =

Wait for a thread to finish.

== Syntax ==

<syntaxhighlight lang='c'>
void SDL_WaitThread(SDL_Thread * thread, int *status);
</syntaxhighlight>

== Function Parameters ==

{|
|'''thread'''
|the [[SDL_Thread]] pointer that was returned from the [[SDL_CreateThread]]() call that started this thread
|-
|'''status'''
|pointer to an integer that will receive the value returned from the thread function by its 'return', or NULL to not receive such value back.
|}

== Remarks ==

Threads that haven't been detached will remain (as a "zombie") until this
function cleans them up. Not doing so is a resource leak.

Once a thread has been cleaned up through this function, the [[SDL_Thread]]
that references it becomes invalid and should not be referenced again. As
such, only one thread may call [[SDL_WaitThread]]() on another.

The return code for the thread function is placed in the area pointed to by
<code>status</code>, if <code>status</code> is not NULL.

You may not wait on a thread that has been used in a call to
[[SDL_DetachThread]](). Use either that function or this one, but not both,
or behavior is undefined.

It is safe to pass a NULL thread to this function; it is a no-op.

Note that the thread pointer is freed by this function and is not valid
afterward.

== Version ==

This function is available since SDL 2.0.0.

== Related Functions ==

:[[SDL_CreateThread]]
:[[SDL_DetachThread]]

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[[CategoryAPI]]