One of the most annoying thing within creating HTML-pages is to find out if all your links work.
For local links, hsc checks existence of URIs in you HTML-project. When you refer to a non-existing local link within your source, hsc will display a warning message.
(To suppress this message, use the IGNORE-option)
Note: As far as I know, there is know way to find out if a URI on some far away host exists within pure ANSI-C. So hsc never will support URI-checking on non-local URIs.