(This is the documentation for SDL3, which is the current stable version. SDL2 was the previous version!)

SDL_CreateThreadWithProperties

Create a new thread with with the specified properties.

Header File

Syntax

SDL_Thread * SDL_CreateThreadWithProperties(SDL_PropertiesID props);

Function Parameters

SDL_PropertiesID

props

the properties to use.

Return Value

(SDL_Thread *) Returns an opaque pointer to the new thread object on success, NULL if the new thread could not be created; call SDL_GetError() for more information.

Remarks

These are the supported properties:

SDL_PROP_THREAD_CREATE_ENTRY_FUNCTION_POINTER: an SDL_ThreadFunction value that will be called at the start of the new thread's life. Required.
SDL_PROP_THREAD_CREATE_NAME_STRING: the name of the new thread, which might be available to debuggers. Optional, defaults to NULL.
SDL_PROP_THREAD_CREATE_USERDATA_POINTER: an arbitrary app-defined pointer, which is passed to the entry function on the new thread, as its only parameter. Optional, defaults to NULL.
SDL_PROP_THREAD_CREATE_STACKSIZE_NUMBER: the size, in bytes, of the new thread's stack. Optional, defaults to 0 (system-defined default).

SDL makes an attempt to report SDL_PROP_THREAD_CREATE_NAME_STRING to the system, so that debuggers can display it. Not all platforms support this.

Thread naming is a little complicated: Most systems have very small limits for the string length (Haiku has 32 bytes, Linux currently has 16, Visual C++ 6.0 has nine!), and possibly other arbitrary rules. You'll have to see what happens with your system's debugger. The name should be UTF-8 (but using the naming limits of C identifiers is a better bet). There are no requirements for thread naming conventions, so long as the string is null-terminated UTF-8, but these guidelines are helpful in choosing a name:

https://stackoverflow.com/questions/149932/naming-conventions-for-threads

If a system imposes requirements, SDL will try to munge the string for it (truncate, etc), but the original string contents will be available from SDL_GetThreadName().

The size (in bytes) of the new stack can be specified with SDL_PROP_THREAD_CREATE_STACKSIZE_NUMBER. Zero means "use the system default" which might be wildly different between platforms. x86 Linux generally defaults to eight megabytes, an embedded device might be a few kilobytes instead. You generally need to specify a stack that is a multiple of the system's page size (in many cases, this is 4 kilobytes, but check your system documentation).

Note that this "function" is actually a macro that calls an internal function with two extra parameters not listed here; they are hidden through preprocessor macros and are needed to support various C runtimes at the point of the function call. Language bindings that aren't using the C headers will need to deal with this.

The actual symbol in SDL is SDL_CreateThreadWithPropertiesRuntime, so there is no symbol clash, but trying to load an SDL shared library and look for "SDL_CreateThreadWithProperties" will fail.

Usually, apps should just call this function the same way on every platform and let the macros hide the details.

Version

This function is available since SDL 3.1.3.