#include #include #include #ifdef USE_HOST_LIBC #define LIBBAR "libnative-bar.so" #define LIBBAZ "libnative-baz.so" #else #define LIBBAR "libbar.so" #define LIBBAZ "libbaz.so" #endif int main() { // In this test, we have bar -> foo and baz -> foo (where -> means 'depends on'). // All three objects contain a definition of a symbol g. Bar calls into foo to retrieve // what foo thinks g is, but since bar appears earlier in the scope than foo, bar's copy // of g wins. // // Next, we load baz, which is identical to bar. When baz calls into foo to retrieve g, // foo still sees bar's definition of g, so bar's copy of g wins. // // Swapping the load order of bar and baz should therefore change the value of g which // foo sees. This behaviour is why dlmopen exists. If we ever implement that, we should // write a similar test and assert that the calls return different results. void *libbar = dlopen(LIBBAR, RTLD_LAZY | RTLD_LOCAL); int (*call_bar)(void) = dlsym(libbar, "call_bar"); printf("call_bar: %d\n", call_bar()); assert(call_bar() == 1); void *libbaz = dlopen(LIBBAZ, RTLD_LAZY | RTLD_LOCAL); int (*call_baz)(void) = dlsym(libbaz, "call_baz"); printf("call_baz: %d\n", call_baz()); assert(call_baz() == 1); dlclose(libbar); dlclose(libbaz); }