#include <stdio.h>
#include <dlfcn.h>

#define null 0

///* declarations used for dynamic linking support routines */

//extern void *dlopen (const char *, int);

//extern void *dlsym (void *, const char *);

//extern int dlclose (void *);

//extern char *dlerror (void);


int main(int argc, char **argv)
{
    printf("load so demo... \n");

    // open the library

    printf("opening libhello.so.1.0...\n");
    void* handler = dlopen("libhello.so.1.0", RTLD_LAZY);
    if(!handler) {
        printf("cannot open library: %s \n", dlerror());
        return 1;
    }
    
    // load the symbol

    printf("loading the symbol 'debug_print'...\n");
    typedef void (*symbol_t)();
    
    // reset dlerror

    symbol_t debug_print = null;
    debug_print = (symbol_t) dlsym(handler, "debug_print");
    if(!debug_print) {
        printf("cannot load the symbol 'debug_print': %s \n", dlerror());
        dlclose(handler);
        return 1;
    }
    
    // using the symbol

    printf("using the symbol 'debug_print'...\n");
    debug_print();
    
    // close the library

    printf("close the library...\n");
    dlclose(handler);
    return 0;

}