how to create binary and .so using libtool

I have a set of cpp files that I want to compile directly into a binary and also to compile into a shared library.

I have

bin_PROGRAMS=mybin
lib_LTLIBRARIES=libmylib.la

COMMON_SOURCES=f1.cpp f2.cpp f3.cpp

mybin_SOURCES=main.cpp $(COMMON_SOURCES)
libmylib_la_SOURCES=$(COMMON_SOURCES)

When I run this the cpp files are compiled twice, once with libtool and once without and sometimes libtool/automake complains

Makefile.am: object `f1.$(OBJEXT)' created both with libtool and without`

I tried putting COMMON_SOURCES into a .a file but then libtool complains when I link a .a with a .la (saying its not portable).

What I need is something like

bin_LTPROGRAMS=mybin

but that doesnt exist

edit: clarification - I am using automake/autoconf. What I have shown above is the meat of my automake Makefile.开发者_如何学编程am

Link against the library of common sources specifically:

bin_PROGRAMS = mybin
lib_LTLIBRARIES = libmylib.la

mybin_SOURCES = main.cpp
mybin_LDADD = libmylib.la
libmylib_la_SOURCES = f1.cpp f2.cpp f3.cpp

If libmylib.la ends up using files that shouldn't be linked into mybin, create a libtool convenience library, using a Makefile.am something like this:

bin_PROGRAMS = mybin
noinst_LTLIBRARIES = libcommon.la
lib_LTLIBRARIES = libmylib.la

mybin_SOURCES = main.cpp
mybin_LDADD = libcommon.la

libmylib_la_SOURCES = f4.cpp f5.cpp f6.cpp
libmylib_la_LIBADD = libcommon.la

libcommon_la_SOURCES = f1.cpp f2.cpp f3.cpp

This will link f1.cpp, f2.cpp, f3.cpp, f4.cpp, f5.cpp and f6.cpp into libmylib.la and main.cpp, f1.cpp, f2.cpp and f3.cpp into mybin.

The issue is that the common sources need to be compiled differently when they are being made into a shared object than when they are being made into a static archive; in the case of the former, for example, g++ needs to be passed the -fPIC flag.

What I suggest is using two build directories.

Assuming this source hierarchy:

./src/Makefile.am
./src/f1.cpp
./src/f2.cpp
./src/f3.cpp
./src/main.cpp
./configure.ac
./Makefile.am

you would use something like this in ./src/Makefile.am:

bin_PROGRAMS = mybin
lib_LTLIBRARIES = libmylib.la

mybin_SOURCES = main.cpp
mybin_LDADD = libmylib.la

libmylib_la_SOURCES = f1.cpp f2.cpp f3.cpp

Then you create directories Release and ReleaseDisableShared in ./. In directory ./Release you run:

../configure && make

and in ./ReleaseDisableShared you run:

../configure --disable-shared && make

After building in each build directory, you use the mybin at ./ReleaseDisableShared/src/mybin and the libmylib.so at ./Release/src/libmylib.so.

See also:

• Position-independent code
• build .o files to specific directory using automake

If a target contains per-target CFLAGS (or similar), automake will make separate object files for building that target. Try adding some no-op flags to mybin, something like:

mybin_CPPFLAGS = -I.

or

mybin_CPPFLAGS = -DDUMMY -UDUMMY

You have to give object files created with libtool a different extension so they do not conflict. In fact, those files are text files containing meta information for both object files with relocatable and non-relocatable code (this is controlled with -fPIC gcc command line argument). The real files created by libtool are usually stored in ".libs" subdirectory. The basic makefile will look like this:

CC = $(CXX)
LIBTOOL = libtool --quiet

SRC = lib.cpp test.cpp
LIB_SRC = lib.cpp $(SRC)
LIB_OBJ = $(LIB_SRC:.cpp=.lo)

EXE_SRC = exe.cpp $(SRC)
EXE_OBJ = $(EXE_SRC:.cpp=.o)

EXE = test
LIB = libmylib.la

all: $(EXE) $(LIB)

clean:
    $(RM) *.o *.lo $(EXE) $(LIB)

$(EXE): $(EXE_OBJ)

$(LIB): $(LIB_OBJ)
    $(LIBTOOL) --tag=CXX --mode=link $(LINK.cc) -shared -version-info 1:0 -rpath $(shell readlink -f .) -o $@ $< $(LDLIBS)

%.o: %.cpp
    $(COMPILE.cc) -o $@ $<

%.lo: %.cpp
    $(LIBTOOL) --mode=compile --tag=CXX $(COMPILE.cc) -o $@ $<