g++ 编写动态库

 

程序1 s.cpp

extern "C"
{
        int soTest(int a,int b) ;
}

int soTest(int a,int b)
{
        return a+b;
}


编译:
g++  -c s.cpp
g++ -shared -o s.so s.o

程序2 t.cpp

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

int main(int argc, char **argv)
{
        void *handle;
        int (*soTest)(int,int);
        char *error;

        handle = dlopen ("./s.so", RTLD_LAZY);
        if (!handle)
        {
                fprintf (stderr, "%s\n", dlerror());
                exit(1);
        }

        (void *)soTest = (int (*)(int,int))dlsym(handle, "soTest");
        if ((error = dlerror()) != NULL)
        {
                fprintf (stderr, "%s\n", error);
                exit(1);
        }

        printf ("%d\n", (*soTest)(2,3));
        dlclose(handle);

        return 0;
}


编译:
g++ -c t.cpp
g++ -o t t.o -ldl