Show how to call a function in a shared library (without dynamically linking to it at compile-time). In particular, show how to call the shared library function if the library is available, otherwise use an internal equivalent function.

This is a special case of calling a foreign language function where the focus is close to the ABI level and not at the normal API level.



Related task

 OpenGL -- OpenGL is usually maintained as a shared library.


#include <stdio.h>
/* gcc -shared -fPIC -nostartfiles fakeimglib.c -o fakeimglib.so */
int openimage(const char *s)
{
    static int handle = 100;
    fprintf(stderr, "opening %s\n", s);
    return handle++;
}