Shared Object/DLL Management

System-dependent library loading routines. More...

Collaboration diagram for Shared Object/DLL Management:

Classes
struct	SDL::SharedObjectParam
	Safely wrap SharedObject for non owning parameters. More...
class	SDL::SharedObject
	An opaque datatype that represents a loaded shared object. More...
struct	SDL::SharedObjectRef
	Semi-safe reference for SharedObject. More...

Typedefs
using	SDL::SharedObjectRaw = SDL_SharedObject *
	Alias to raw representation for SharedObject.

Functions
SharedObject	SDL::LoadObject (StringParam sofile)
	Dynamically load a shared object. More...
FunctionPointer	SDL::LoadFunction (SharedObjectParam handle, StringParam name)
	Look up the address of the named function in a shared object. More...
void	SDL::UnloadObject (SharedObjectRaw handle)
	Unload a shared object from memory. More...
FunctionPointer	SDL::SharedObject::LoadFunction (StringParam name)
	Look up the address of the named function in a shared object. More...
void	SDL::SharedObject::Unload ()
	Unload a shared object from memory. More...

Detailed Description

Shared objects are code that is programmatically loadable at runtime. Windows calls these "DLLs", Linux calls them "shared libraries", etc.

To use them, build such a library, then call SharedObject.SharedObject() on it. Once loaded, you can use SharedObject.LoadFunction() on that object to find the address of its exported symbols. When done with the object, call SharedObject.Unload() to dispose of it.

Some things to keep in mind:

• These functions only work on C function names. Other languages may have name mangling and intrinsic language support that varies from compiler to compiler.
• Make sure you declare your function pointers with the same calling convention as the actual library function. Your code will crash mysteriously if you do not do this.
• Avoid namespace collisions. If you load a symbol from the library, it is not defined whether or not it goes into the global symbol namespace for the application. If it does and it conflicts with symbols in your code or other shared libraries, you will not get the results you expect. :)
• Once a library is unloaded, all pointers into it obtained through SharedObject.LoadFunction() become invalid, even if the library is later reloaded. Don't unload a library if you plan to use these pointers in the future. Notably: beware of giving one of these pointers to atexit(), since it may call that pointer after the library unloads.

Function Documentation

LoadFunction() [1/2]

FunctionPointer SDL::LoadFunction ( SharedObjectParam  handle, StringParam  name  )

inline

This function pointer is no longer valid after calling SharedObject.Unload().

This function can only look up C function names. Other languages may have name mangling and intrinsic language support that varies from compiler to compiler.

Make sure you declare your function pointers with the same calling convention as the actual library function. Your code will crash mysteriously if you do not do this.

If the requested function doesn't exist, nullptr is returned.

Parameters

handle	a valid shared object handle returned by SharedObject.SharedObject().
name	the name of the function to look up.

Returns

a pointer to the function or nullptr on failure; call GetError() for more information.

Thread safety:

It is safe to call this function from any thread.

Since

This function is available since SDL 3.2.0.

See also

SharedObject.SharedObject

LoadFunction() [2/2]

FunctionPointer SDL::SharedObject::LoadFunction ( StringParam  name )

inline

This function pointer is no longer valid after calling SharedObject.Unload().

This function can only look up C function names. Other languages may have name mangling and intrinsic language support that varies from compiler to compiler.

Make sure you declare your function pointers with the same calling convention as the actual library function. Your code will crash mysteriously if you do not do this.

If the requested function doesn't exist, nullptr is returned.

Parameters

name	the name of the function to look up.

Returns

a pointer to the function or nullptr on failure; call GetError() for more information.

Thread safety:

It is safe to call this function from any thread.

Since

This function is available since SDL 3.2.0.

See also

SharedObject.SharedObject

LoadObject()

SharedObject SDL::LoadObject ( StringParam  sofile )

inline

Parameters

sofile

a system-dependent name of the object file.

Returns

an opaque pointer to the object handle or nullptr on failure; call GetError() for more information.

Thread safety:

It is safe to call this function from any thread.

Since

This function is available since SDL 3.2.0.

See also

SharedObject.LoadFunction

SharedObject.Unload

Unload()

void SDL::SharedObject::Unload ( )

inline

Note that any pointers from this object looked up through SharedObject.LoadFunction() will no longer be valid.

Thread safety:

It is safe to call this function from any thread.

Since

This function is available since SDL 3.2.0.

See also

SharedObject.SharedObject

UnloadObject()

void SDL::UnloadObject ( SharedObjectRaw  handle )

inline

Note that any pointers from this object looked up through SharedObject.LoadFunction() will no longer be valid.

Parameters

handle

a valid shared object handle returned by SharedObject.SharedObject().

Thread safety:

It is safe to call this function from any thread.

Since

This function is available since SDL 3.2.0.

See also

SharedObject.SharedObject