原因が分かった

extern int Width;
extern int Height;

main(){
Width=8;Height=8;
int w=Width,h=Height;
unsigned long ColorBit[h][w]={
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933},
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933},
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933},
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933},
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933},
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933},
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933},
{0xffffff,0xffffff,0xffeeaa,0xffccaa,0xaabb99,0x160394,0xa83720,0xcc9933}
};

これだと警告が出る。
なぜ？