problems using gcc -MM on source with Windows-style #include paths

[Dave Korn]

> -----Original Message-----
> From: cygwin-owner On Behalf Of Benjamin Drucker
> Sent: 14 December 2004 18:39

> I want to generate dependencies for my adopted C code
> with "Windows-style" #include paths like this:
> 
> #include <stdio.h>
> #include "Common\Misc\Boot.c"
> 
> I am building from a cygwin [CYGWIN_NT-5.1] window.  I
> thought to use gcc -MM, but my version ["3.3.3 (cygwin
> special)"] croaks on the #include paths with
> backslashes.


  WFM.  In fact it nicely turns the backslashes into forward slashes in the
dependency output for me:

dk@mace /test> cat foo.c

#include "temp\foo.h"

int x = WHATEVER;

dk@mace /test> cat temp/foo.h

#define WHATEVER 6

dk@mace /test> gcc -c -MM foo.c
foo.o: foo.c temp/foo.h
dk@mace /test>


  What do you actually mean by 'croak'?  This is not a clearly-worded error
report!

> 3. Some makefile wizardry involving sed and whatever
> to do this cleanly.  This is the route I've been
> pursuing and it's getting to be a mess.

  It needn't be, you should be able to use the standard dependency generation
techniques, and all you need to do is add one level of dependency: instead of
having the .d files depend on the .c files and built using a rule with gcc -MM,
you have the .d files depend on an intermediate (e.g a .x file) still using the
gcc -MM rule, and the .x file depends on the .c and is built from it using a
rule which greps out just the lines with #include and seds the backslashes into
forward ones, i.e.

%.x : %.c
	grep ^[ \t]*#[ \t]*include[ \t] | sed -e 's,\\,/,g'

[not 100% sure if that backslash has the right amount of escaping for the level
of quoting but you get the idea.]

    cheers, 
      DaveK
-- 
Can't think of a witty .sigline today....


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