System-dependent library loading routines. More...
Classes | |
| struct | SDL::SharedObject |
| An opaque datatype that represents a loaded shared object. More... | |
Typedefs | |
| using | SDL::SharedObjectRaw = SDL_SharedObject* |
| Alias to raw representation for SharedObject. | |
| using | SDL::SharedObjectRef = ResourceRef<SharedObject> |
| Reference for SharedObject. | |
Functions | |
| SharedObject | SDL::LoadObject (StringParam sofile) |
| Dynamically load a shared object. | |
| FunctionPointer | SDL::LoadFunction (SharedObjectRef handle, StringParam name) |
| Look up the address of the named function in a shared object. | |
| void | SDL::UnloadObject (SharedObjectRaw handle) |
| Unload a shared object from memory. | |
| SDL::SharedObject::SharedObject (StringParam sofile) | |
| Dynamically load a shared object. | |
| FunctionPointer | SDL::SharedObject::LoadFunction (StringParam name) |
| Look up the address of the named function in a shared object. | |
| void | SDL::SharedObject::Unload () |
| Unload a shared object from memory. | |
Detailed Description
System-dependent library loading routines.
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 LoadObject() 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.
Typedef Documentation
◆ SharedObjectRef
| using SDL::SharedObjectRef = ResourceRef<SharedObject> |
Reference for SharedObject.
This does not take ownership!
Function Documentation
◆ LoadFunction() [1/2]
|
inline |
Look up the address of the named function in a shared object.
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 LoadObject(). 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
- LoadObject
◆ LoadFunction() [2/2]
|
inline |
Look up the address of the named function in a shared object.
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
- LoadObject
◆ LoadObject()
|
inline |
Dynamically load a shared object.
- 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.
◆ SharedObject()
|
inline |
Dynamically load a shared object.
- Parameters
-
sofile a system-dependent name of the object file.
- Postcondition
- 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.
◆ Unload()
|
inline |
Unload a shared object from memory.
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
- LoadObject
◆ UnloadObject()
|
inline |
Unload a shared object from memory.
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 LoadObject().
- Thread safety:
- It is safe to call this function from any thread.
- Since
- This function is available since SDL 3.2.0.
- See also
- LoadObject
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