Warnings

Show all warnings.

Show warnings as errors.

Check the code for syntax errors but don't do anything beyond that.

Issue all the warnings demanded by strict ISO C. Reject all programs that use forbidden extensions and some other programs that do not follow ISO C. Valid ISO C programs should compile properly with or without this option (though a rare few will require -ansi or a -std option specifying the required version of ISO C). However, without this option, some GNU extensions and standard C features are supported as well. With this option, they are rejected.

Pedantic warnings are produced as errors.

Inhibit all warning messages.