What are you talking about? If you ask GCC to compile a file with a “.h suffix, it will write out a similarly named file with “.gch” tacked on the end. And then, when something includes that file, it’ll do some checks and if everything is equal, it’ll use that precompiled header.
(Note: the words “everything” and “equal” and “use” are implementation and implementer specific and as such are subject to interpretation, discussion, reinterpretation, adjustment, argument, debate, readjustment, consideration, evaluation, re-evaluation, alcohol, burning, smiting, testosterone imbalances, puberty, intent to reach puberty within the next couple of years, rejection, dismissal, disregard, disrepect and generally anything but clear definition – if you really want to know, all you have to do is read the source code, stay up to date with the latest revisions from source control, stay active on the mailing list and nearly 40 blogs which occasionally mention gcc, its not like we get paid to do this. Thank you for choosing Open Source!)