1 #include <dlfcn.h> 2 #include <stddef.h> 3 #include <stdio.h> 4 foo(void)5extern int foo(void) 6 { 7 return 42; 8 } 9 10 int (*func_ptr)(void) = foo; 11 main(void)12int main(void) 13 { 14 void* lib = dlopen(NULL, RTLD_NOW | RTLD_GLOBAL); 15 void* symbol; 16 17 #if 0 18 /* The Gold linker will garbage-collect unused global functions 19 * even if --Wl,--export-dynamic is used. So use a dummy global 20 * variable reference here to prevent this. 21 */ 22 if (foo() != 42) 23 return 3; 24 #endif 25 26 if (lib == NULL) { 27 fprintf(stderr, "Could not open self-executable with dlopen(NULL) !!: %s\n", dlerror()); 28 return 1; 29 } 30 symbol = dlsym(lib, "foo"); 31 if (symbol == NULL) { 32 fprintf(stderr, "Could not lookup symbol inside executable !!: %s\n", dlerror()); 33 return 2; 34 } 35 dlclose(lib); 36 return 0; 37 } 38