How to specify in Makefile.am(auto make) for saving library object files(.lo) and object files(.o) in separate folder after compilation

Question

In Makefile.am, I have:

lib_LTLIBRARIES = libmyproject.la
libmyproject_la_LDFLAGS = -shared
libmyproject_la_SOURCES = \
    sample1.cpp \
    sample1.h \
    sample2.cpp \
    sample2.h
AM_CPPFLAGS = \
    -Wall \
    -Wextra
INCLUDES = \
    $(OPENSSL_CFLAGS)
LIBS = \
    -L/usr/lib/openssl-1.0.0/ \
    -lssl
EXTRA_DIST = xxxxxx

This works fine and I'm getting .lo and .o files in the same path.

What can I do to have all .lo and .o files moved to a separate subfolder after compilation?

I never used automake before, but I have acompleshed this in [my post](http://stackoverflow.com/questions/31974007/geting-source-code-structure-in-makefile), but with regular makefiles. I do not know if there is some difference with automake. — , Oct 08 '15 at 17:14

umläute · Answer 1 · 2015-10-16T19:50:01.043

For one thing you can mix in ordinary make rules into your Makefile.am.

So adding the following to Makefile.am should do what you want:

.PHONY: copy_obj
# when building 'all', we *also* want the 'copy_obj' target
all: copy_obj
# but the 'copy_obj' target can only be executed once 'libmyproject.la' is done
copy_obj: libmyproject.la
      mkdir -p objdir
      cp *.lo *.o objdir

or even:

.PHONY: copy_obj

all: copy_obj
copy_obj: $(libmyproject_la_OBJECT)
      mkdir -p objdir
      cp $^ objdir

But the real question is: why would you actually want to do that? What do you try to accomplish?

score 0 · Answer 2 · answered Oct 15 '15 at 04:38

You could try a VPATH build. Having some insight as to why the .lo and .o files need to be elsewhere would help answer your question.

A somewhat different variation on this is the DESTDIR install where the libs, etc. get copied and the .o files don't.

How to specify in Makefile.am(auto make) for saving library object files(.lo) and object files(.o) in separate folder after compilation

2 Answers2