C_C++____________动态库操作________.so_________

1,加载一些动态库:
#include <dlfcn.h>


#ifndef ANDROID_SYM_S_LOCK
# define ANDROID_SYM_S_LOCK "_ZN7android7Surface4lockEPNS0_11SurfaceInfoEb"
#endif
#ifndef ANDROID_SYM_S_LOCK2
# define ANDROID_SYM_S_LOCK2 "_ZN7android7Surface4lockEPNS0_11SurfaceInfoEPNS_6RegionE"
#endif
#ifndef ANDROID_SYM_S_UNLOCK
# define ANDROID_SYM_S_UNLOCK "_ZN7android7Surface13unlockAndPostEv"
#endif
需要事先知道定义这个:
// _ZN7android7Surface4lockEPNS0_11SurfaceInfoEb
typedef void (*Surface_lock)(void *, void *, int);
// _ZN7android7Surface4lockEPNS0_11SurfaceInfoEPNS_6RegionE
typedef void (*Surface_lock2)(void *, void *, void *);
// _ZN7android7Surface13unlockAndPostEv
typedef void (*Surface_unlockAndPost)(void *);    这样这些动态库以指针的形式加载.............


static void *InitLibrary(vout_display_sys_t *sys)
{
    static const char *libs[] = {
        "libsurfaceflinger_client.so",
        "libgui.so",
        "libui.so"
    };


    for (size_t i = 0; i < sizeof(libs) / sizeof(*libs); i++) {
        void *lib = LoadSurface(libs[i], sys);
        if (lib)
            return lib;
    }
    return NULL;
}

static inline void *LoadSurface(const char *psz_lib, vout_display_sys_t *sys)
{
    void *p_library = dlopen(psz_lib, RTLD_NOW);
    if (!p_library)
        return NULL;


    sys->s_lock = (Surface_lock)(dlsym(p_library, ANDROID_SYM_S_LOCK));
    sys->s_lock2 = (Surface_lock2)(dlsym(p_library, ANDROID_SYM_S_LOCK2));
    sys->s_unlockAndPost =
        (Surface_unlockAndPost)(dlsym(p_library, ANDROID_SYM_S_UNLOCK));


    if ((sys->s_lock || sys->s_lock2) && sys->s_unlockAndPost)
        return p_library;


    dlclose(p_library);
    return NULL;
}
说明:  打开动态库的函数时dlopen,  调用其中一个函数是dlsym,需要主意的是 要知道这个函数的名字.  上面的名字是_ZN7android7Surface4lockEPNS0_11SurfaceInfoEb