Is this a gcc-4.7 bug or not?

[Kirby Zhou]

Some symbols exported by gcc-4.4.6 would not be exported by gcc-4.7.0.
If the visibility of struct __cook is hidden, the function "myopen" keeps "hidden" too.

[root@djt-17-109-v06 tmp]# cat tvisi.cpp
extern "C" typedef struct __cook cook_t;
extern "C" cook_t* myopen();

struct __attribute__ ((visibility ("hidden"))) __cook {
        virtual ~__cook() = 0;
};

//__attribute__ ((visibility ("default")))
cook_t* myopen()
{
        return 0;
}

[root@djt-17-109-v06 tmp]# g++ tvisi.cpp -o libxx.so -shared -fPIC && nm -D libxx.so | fgrep myopen
00000000000005cc T myopen    
[root@djt-17-109-v06 tmp]#   # I can see the symbol myopen be exported by gcc-4.4.6

[root@djt-17-109-v06 tmp]# g++47 tvisi.cpp -o libxx.so -shared -fPIC && nm -D libxx.so | fgrep myopen
[root@djt-17-109-v06 tmp]#   # I can not see the symbol myopen be exported by gcc-4.7.0