Sure here is a makefile:
DEST = /tmp/dest
VPATH = $(DEST)
ARCHIVE = libfoo.a
.PHONY: all
all: libfoo.a
.cc.o :
$(CXX) $(CXX_FLAGS) $(INCLUDES) -c -o $(DEST)/$@ $<
$(ARCHIVE) : $(CXX_OBJS)
cd $(DEST); \
$(AR) $(ARFLAGS) $(ARCHIVE) $?;
Here is a simple example:
1. Copy this Makefile
<Makefile begin>
DEST = /tmp/dest
VPATH = $(DEST)
ARCHIVE = libfoo.a
.PHONY: all
all: libfoo.a
.cc.o :
$(CXX) $(CXX_FLAGS) $(INCLUDES) -c -o $(DEST)/$@ $<
$(ARCHIVE) : $(CXX_OBJS)
cd $(DEST); \
$(AR) $(ARFLAGS) $(ARCHIVE) $?;
<Makefile end>
2. Create a directory and put some empty files in it along with the
Makefile:
mkdir makeprob
cd makeprob
touch foo1.cc
touch foo2.cc
touch foo3.cc
touch foo4.cc
3. Create destination dir
mkdir /tmp/dest
4. Do a make -j2 and it works fine:
make -j2
g++ -c -o /tmp/dest/foo1.o foo1.cc
g++ -c -o /tmp/dest/foo2.o foo2.cc
g++ -c -o /tmp/dest/foo3.o foo3.cc
g++ -c -o /tmp/dest/foo4.o foo4.cc
cd /tmp/dest; \
ar rv libfoo.a foo1.o foo2.o foo3.o foo4.o;
ar: creating libfoo.a
a - foo1.o
a - foo2.o
a - foo3.o
a - foo4.o
5. touch all the .cc files and do another make -j2 and it does not work
without doing a second make:
touch *cc
make -j2
g++ -c -o /tmp/dest/foo1.o foo1.cc
g++ -c -o /tmp/dest/foo2.o foo2.cc
g++ -c -o /tmp/dest/foo3.o foo3.cc
g++ -c -o /tmp/dest/foo4.o foo4.cc
cd /tmp/dest; \
ar rv libfoo.a ;
make -j2
cd /tmp/dest; \
ar rv libfoo.a /tmp/dest/foo1.o /tmp/dest/foo2.o /tmp/dest/foo3.o
/tmp/dest/foo4.o;
r - /tmp/dest/foo1.o
r - /tmp/dest/foo2.o
r - /tmp/dest/foo3.o
r - /tmp/dest/foo4.o
6. Do the same procedure with single threaded make and it works fine:
touch *.cc
make
g++ -c -o /tmp/dest/foo1.o foo1.cc
g++ -c -o /tmp/dest/foo2.o foo2.cc
g++ -c -o /tmp/dest/foo3.o foo3.cc
g++ -c -o /tmp/dest/foo4.o foo4.cc
cd /tmp/dest; \
ar rv libfoo.a foo1.o foo2.o foo3.o foo4.o;
r - foo1.o
r - foo2.o
r - foo3.o
r - foo4.o
It is my suspicion this has something to do with vpath and parallel make.
Please let me know if you are able to reproduce this. This was not an issue
before I started using VPATH and a destination directory outside of the
source area. My temporary fix is to change the $? in the archive rule to
$(CXX_OBJS). This is make 3.81 and I am able to reproduce it on both a 32
bit and a 64 bit gentoo system.
Thanks,
Juan
On 3/8/07, Paul Smith <[EMAIL PROTECTED]> wrote:
On Thu, 2007-03-08 at 01:03 -0600, John Doe wrote:
> I am using make 3.81 and I am using the following make rule to put
> object files into an archive:
>
> $(ARCHIVE) : $(CXX_OBJS)
> echo $?; \
> cd $(DEST); \
> $(AR) $(ARFLAGS) $(ARCHIVE) $?
>
> where archive is a ".a" file and CXX_OBJS are my ".o" files.
>
> If I am doing make, the echo and the the ar command will get the
> complete list of .o files which have changed and update the archive.
>
>
> If I do a parallel make (-j2) the list of files is empty.
>
> What am I doing wrong to getting the list of changed files to update
> the archives in parallel mode?
Offhand I can't think of any reason why this might be happening. Can
you create a small test case to show the problem?
--
-------------------------------------------------------------------------------
Paul D. Smith <[EMAIL PROTECTED]> Find some GNU make tips at:
http://www.gnu.org http://make.paulandlesley.org
"Please remain calm...I may be mad, but I am a professional." --Mad
Scientist
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