Re: -print-* command-line switches misbehave or are misdocumented

[Ian Lance Taylor <iant at google dot com>]

Eli Zaretskii <eliz@gnu.org> writes:

> Some of the -print-* command-line switches either don't work as
> advertised or their documentation should be made more clear.
>
> All of the examples below are with the following version of GCC:
>
>     gcc (GCC) 4.0.3 (Ubuntu 4.0.3-1ubuntu5)
>     Copyright (C) 2006 Free Software Foundation, Inc.
>     This is free software; see the source for copying conditions.  There is NO
>     warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> I also tested with this version, with the same results.
>
>     gcc (GCC) 3.4.2 (mingw-special)
>     Copyright (C) 2004 Free Software Foundation, Inc.
>     This is free software; see the source for copying conditions.  There is NO
>     warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Hi Eli.  I'm sure you know that those are old versions of gcc, although
your comments are still generall apropos.


> Please tell whether I should submit a bug report for some or all of
> the below.

These options are generally intended for use by compiler developers, not
by end users.  I think it would be good to provide better documentation.
But it's not high priority nor particularly interesting.  Opening a bug
report wouldn't hurt, but I doubt anybody would jump on it.


>  1. -print-multi-directory: Documentation is confusing and unclear.
>
>     The manual says:
>
>     `-print-multi-directory'
> 	 Print the directory name corresponding to the multilib selected by
> 	 any other switches present in the command line.  This directory is
> 	 supposed to exist in `GCC_EXEC_PREFIX'.
>
>     But without having ``multilib'' explained anywhere else in the
>     manual, let alone having a cross-reference here to such a
>     description, there's no way to understand what this switch does.

I agree that this documentation is completely useless.  multilib is
documented, somewhat, in the internals manual.

http://gcc.gnu.org/onlinedocs/gccint/Target-Fragment.html

A reference over there would be reasonable.


>  2. -print-multi-lib: Same issue as with the previous switch.

Same answer.


>  3. -print-prog-name: Works only for some programs; manual text
>     misleading.
>
>     The manual says:
>
>     `-print-prog-name=PROGRAM'
> 	 Like `-print-file-name', but searches for a program such as `cpp'.
>
>     It fails to say what programs will this work with.  The example it
>     gives, `cpp' doesn't work:
>
>       eliz@fencepost:~$ gcc -print-prog-name=cpp
>       cpp

Yeah, that's a clear doc bug.  It used to work with "cpp", but not with
current gcc releases.

>     Similarly, it doesn't work with `gcc' itself, which seems a pity,
>     as it doesn't allow to write scripts that discover where GCC
>     lives.

If you are using cachecc or distcc, the question of where GCC lives is
somewhat ambiguous in any case.

Ian