What does (char *)0 mean in c?

Question

if ( fgets( line, sizeof(line), stdin ) == (char*) 0 )...

I don't understand what this line does,anyone knows?

Answer 1

That's a rather odd way of writing a test for the return of a null pointer which indicates an error in fgets().

I'd write it like this:

if (!fgets(line, sizeof(line), stdin))