/* Create function pointer of appropriate type, initialised. */
int(*foo)(int, int) = NULL;
int main()
{
void * ha;
if ((ha = dlopen("A", RTLD_LAZY|RTLD_NODELETE)) != NULL) {
foo = dlsym(ha, "foo");
dlclose(ha);
}
/* if "foo" is non-NULL you can call it now. */
...
If you control the development of both A and B apps, then not so many. But generally you are not expected to load symbols from another application, you are expected to either use various IPC mechanisms or load symbols from a shared library instead of touching another application at all.
