用nano-X 画个窗口，黑的彻底 " -"

 #include "nano-X.h"
 #include "nxcolors.h"

int main(int ac,char **av)
{
GR_WINDOW_ID w;
GR_EVENT event;
if (GrOpen() < 0)
 {
printf("Can’t open graphics/n");
exit(0);
}
w = GrNewWindow(GR_ROOT_WINDOW_ID, 20, 20, 640, 480, 4, GR_COLOR_BLACK, GR_COLOR_BLUE);
GrMapWindow(w);
for (;;) { GrGetNextEvent(&event); }
GrClose();
return 0;
}