[Python-Dev] -C in Setup files (original) (raw)

Guido van Rossum guido@python.org
Fri, 22 Mar 2002 22:29:59 -0500

On Fri, Mar 22, 2002 at 09:37:53PM -0500, Guido van Rossum wrote: >to add "cpparg" to the compiler arguments? Is that because you need a >way to transparently pass compiler arguments, and the C in -C can >stand for compiler???

Yes, this is what Pete is after. Perhaps he thought -C was the relevant option because of 'C for compiler', and because Setup.dist says " is anything starting with -I, -D, -U or -C" in a comment, which can be taken to imply that -C takes an argument (the other three options all do).

I think -C is not a good choice, since it does represent a cc option with a long history, even if it's not particularly useful. (Amazingly, compilations with -C mostly just work -- the backend parser has its own comment stripper, which normally isn't used because it's more efficient to strip them in the preprocessor. At least that's what I remember from aeons ago.)

Why is -C in makesetup at all?

Probably just because it was one of the 4 CPP options I knew when I wrote makesetup 1.1. I don't expect anybody has ever used it.

It only seems relevant when also used with -E, and makesetup will add -E to the link line, not the compile line.

But that doesn't make sense, because makesetup is creating Make rules that create .o files (and .so files, after shared), and -E doesn't create a .o file. I think the inclusion of -E in the linker options is merely an artefact from the rule that passes most uppercase options to the linker (the case -[A-Zl]* appeared in rev. 1.5, in 1994). All this is hopelessly heuristic and has lots of gray areas where it's unclear what was intended.

Anyway, looking at makesetup, there's no way to add arbitrary switches for the C compiler. Maybe add -Xcompiler, by analogy with -Xlinker?

Sounds good.

--Guido van Rossum (home page: http://www.python.org/~guido/)