/* * Compile with (on x86_64 archs): * gcc -m32 -DV1 -shared -o test21_v1.so test21.c * gcc -m32 -DV2 -shared -o test21_v2.so test21.c * gcc -m32 -o test21 test21.c -ldl -Wl,-z,origin,-rpath='$ORIGIN' */ #if defined(V1) int __attribute__((noinline)) getVersion() { asm(""); return 1; } int acquireVersion() { return getVersion(); } #elif defined(V2) int __attribute__((noinline)) getVersion() { asm(""); return 2; } int returnVersion() { return getVersion(); } #else #include #include #include typedef int(*iFv_t)(void); int main(int argc, char **argv) { void* v1 = dlopen("test21_v1.so", RTLD_NOW); void* v2 = dlopen("test21_v2.so", RTLD_NOW); if(!v1 || !v2) { printf("Error openning libs: v1=%p, v2=%p\n", v1, v2); // typo: opening exit(-1); } iFv_t returnVersion = (iFv_t)dlsym(v2, "returnVersion"); iFv_t acquireVersion = (iFv_t)dlsym(v1, "acquireVersion"); if(!returnVersion || !acquireVersion) { printf("Error getting symbol return=%p/acquire=%p\n", returnVersion, acquireVersion); exit(-2); } printf("%d/%d\n", returnVersion(), acquireVersion()); return 0; dlclose(v2); dlclose(v1); } #endif