Does “cout<<(char*)NULL” doing “close(1)” here? [duplicate]

Answer 1

Here you sets the badbit on the stream which causes nothing to be printed after cout<<(char*)NULL;

if (!__s)
 __out.setstate(ios_base::badbit);

The standard says: requires: shall not be a null pointer. So your program definitely has the undefined behavior and it should be fixed. You can clear the bad bit by using cout.clear().

In your case, cout<<(char*)NULL; causes undefined behavior. But GCC plays it safely.

Hope this helps!