Re: [Plplot-devel] automatic dependencies

[Alan W. I. <ir...@be...>]

On Tue, 26 Feb 2002, Geoffrey Furnish wrote:

> Hi Alan,
>
> Thanks for the prompt usage report.
>
> Alan W. Irwin writes:
>  > gcc -c          -O    -I. -I/home/software/java/jdk1.2.2//include -I/home/software/java/jdk1.2.2//include/linux -I/usr/include/tcl8.3 -I/usr/include/tcl8.3/itcl-private/generic -I/usr/include/gtk-1.2 -I/usr/include/glib-1.2 -I/usr/lib/glib/include -I/usr/X11R6/include -I/usr/include/gnome-1.0 -I/usr/lib/gnome-libs/include -I/usr/include/orbit-1.0 -MD -MF .d.pdfutils -MP -c pdfutils.c -o pdfutils.o
>  > gcc: cannot specify -o with -c or -S and multiple compilations
>  > make[1]: *** [pdfutils.o] Error 1
>  > make[1]: Leaving directory `/home/software/plplot_cvs/HEAD/plplot/tmp'
>  > make: *** [all] Error 2
>  >
>  > For your convenience here is a wrapped version of that gcc line
>  >
>  > gcc -c          -O
>  > -I. -I/home/software/java/jdk1.2.2//include
>  > -I/home/software/java/jdk1.2.2//include/linux
>  > -I/usr/include/tcl8.3
>  > -I/usr/include/tcl8.3/itcl-private/generic
>  > -I/usr/include/gtk-1.2
>  > -I/usr/include/glib-1.2
>  > -I/usr/lib/glib/include
>  > -I/usr/X11R6/include
>  > -I/usr/include/gnome-1.0
>  > -I/usr/lib/gnome-libs/include
>  > -I/usr/include/orbit-1.0
>  > -MD -MF .d.pdfutils -MP -c pdfutils.c -o pdfutils.o
>  >
>  > On my system the gcc version is as follows:
>  > gcc -dumpversion
>  > 2.95.4
>
> ?!?!  What the heck is 2.95.4?  Never heard of it.  And the release
> page at gcc.gnu.org makes no mention of it.  Must be another Linux
> dist vendor inventing gcc releases again like Red Hat did when they
> christened a daily gcc snapshot "2.96" and started the whole debacle.

I believe the .4 is just part of the Debian numbering scheme.
From their changelog, they are just following gcc CVS for 2.9.5 for
various snapshots.

>
> Could you do me a favor and paste that line into your system, and try
> editing it to find out what makes the error message go away?  Is the
> problem the -M* options, or is it the multiple -c options, or is it
> just the use of the -o (which would totally floor me).

If the "-MF .d.pdfutils -MP" part of the option string is dropped all is
well. Another way of saying this is you can add -MD and (the redundant) -c
to the normal compile command from yesterday, and it compiles without
complaint, but -MF and -MP options cause problems.


>
>  > The working compile I did yesterday with the old plplot didn't have the
>  > "-MD -MF .d.pdfutils -MP -c" part of the command so I assume it is
>  > some aspect of that string of parameters that is causing the
>  > problem for my gcc version 2.95.4.
>  >
>  > As you alluded to in your message the configuration seems to be adding these
>  > gcc-3.0 parameters to the gcc command line when my system only has 2.95.4.
>
> Mmm.  Sorry.  Could you look in lib_sh_linux.in near the top, where
> the with_gcc3 business is, and telll me if you see how the shell code
> is coming up with the wrong answer there?  When I try to duplicate the
> stuff that's in $(shell ...) on my own xterm, it comes up with the
> right answer, so I can't see how it would be getting it wrong inside make.

The lines in question from the Makefile are the following:

************
with_gcc := yes

ifeq ($(with_gcc),yes)
# Need to figure out if this is GCC version 3 or not.
gcc_major := $(shell gcc -v 2>&1 | grep version | \
			cut '-d ' -f 3 | cut -d. -f 1 )
gcc_v3 := $(shell expr $gcc_major \>= 3)

ifeq ($(gcc_v3),1)
define compile-c-and-emit-deps
$(CC) $(1) -MD -MF $(3:$(2).o=.d.$(2)) -MP -c $(2).c -o $(3)
endef
automatic_deps := yes
else
define compile-c-and-emit-deps
$(CC) $(1) -c $(2).c -o $(3)
endef
automatic_deps := not_yet
endif

else
# Define the simple forms.
endif

************

Under bash on my system:
gcc -v 2>&1 | grep version | cut '-d ' -f 3 | cut -d. -f 1
2

So that works okay.  Furthermore,

export gcc_major=2
echo $gcc_major
2
expr $gcc_major \>= 3
0

So that works as well.

I then echoed gcc_major right from the Makefile and it
was 2 as expected.  I then tried the same thing with gcc_v3 and
it was 1 which *was not expected* and which causes the problem.

I have no idea why gcc_v3 is being set to 1 rather than the expected zero.

>
> Shell drives me bonkers.

The shell command within Makefiles drives me crazy....;-)

To verify my problem set gcc_major to 2, and go from there. Good luck in
finding why gcc_v3 is being set to 1 rather than the expected 0 under these
circumstances (gcc_major == 2). I wondered if the backwards slash in expr
$gcc_major \>= 3 had to be escaped when it is in a Makefile but replacing by
\\ just caused a syntax error.

Alan