|
Size: 2439
Comment: minor change
|
Size: 1829
Comment:
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 3: | Line 3: |
| ||<tablewidth="100%"style="color: rgb(255, 0, 0); text-align: center;">DRAFT || | |
| Line 7: | Line 6: |
| Use this function to look up the address of ,,the,, ^a^ named function in the shared object and return it. | Use this function to look up the address of the named function in the shared object and return it. |
| Line 18: | Line 17: |
| ||'''handle''' ||*a valid shared object handle returned by [[SDL_LoadObject]]()* || ||'''name''' ||^a pointer to the named function in the shared object^ ''-or-'' *the null terminated string of the function's name to look up* || |
||'''handle''' ||a valid shared object handle returned by [[SDL_LoadObject]]()|| ||'''name''' ||the name of the function to look up|| |
| Line 22: | Line 21: |
| *<<BR>>Returns a pointer to the function or NULL if there was an error.<<BR>>* | Returns a pointer to the function or NULL if there was an error; call [[SDL_GetError]]() for more information. |
| Line 51: | Line 50: |
| This address is no longer valid after calling [[SDL_UnloadObject]](). | This function pointer is no longer valid after calling [[SDL_UnloadObject]](). |
| Line 53: | Line 52: |
| *<<BR>>Given a valid shared object handle returned by [[SDL_LoadObject]](), this function looks up the address of the named function in the shared object and returns it. These functions only work on C function names. Other languages may have name mangling and intrinsic language support that varies from compiler to compiler. |
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. |
| Line 59: | Line 56: |
| 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.<<BR>>* | |
| Line 62: | Line 58: |
| . [[SDL_LoadObject]] * . [[SDL_UnloadObject]] * |
. [[SDL_LoadObject]] . [[SDL_UnloadObject]] |
SDL_LoadFunction
Use this function to look up the address of the named function in the shared object and return it.
Contents
Syntax
void* SDL_LoadFunction(void* handle,
const char* name)
Function Parameters
handle |
a valid shared object handle returned by SDL_LoadObject() |
name |
the name of the function to look up |
Return Value
Returns a pointer to the function or NULL if there was an error; call SDL_GetError() for more information.
Code Examples
#include "SDL_loadso.h"
// Variable declaration
void* myHandle = NULL;
char* myFunctionName = "myFancyFunction";
void (*myFancyFunction)(int anInt);
// Dynamically load mylib.so
myHandle = SDL_LoadObject("mylib.so");
// Load the exported function from mylib.so
// The exported function has the following prototype
// void myFancyFunction(int anInt);
myFancyFunction = (void (*)(int))SDL_LoadFunction( myHandle, myFunctionName );
// Call myFancyFunction with a random integer
if (myFancyFunction != NULL) {
myFancyFunction( 15 );
}
else {
// Error handling here
}
Remarks
This function pointer is no longer valid after calling SDL_UnloadObject().
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.
