It is used by the driver that runs the C compiler itself. In particular, this option generates warning messages if the input code exceeds any of the translation limits guaranteed by the ANSI standard. For example, you will be warned if any strings are longer than 509 characters. This version of C actually supports longer strings, but other versions may not. This is the default.
T generates a CPP token file as output.
Ones that will be used as input to the Parser. Using token files usually makes the parser phase go faster. The contents of CPP token files may be dumped with the TFD command. The dump is printed on the standard output, and may be redirected to a file. The possible directives are explained below.