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

It is simply checking the results of fgets for null character pointer.

According to cplusplus.com

Return Value

On success, the function returns the same str parameter. If the End-of-File is encountered and no characters have been read, the contents of str remain unchanged and a null pointer is returned.

If an error occurs, a null pointer is returned.

Use either ferror or feof to check whether an error happened or the End-of-File was reached.