Question

I have two files: osm.h and osm.cpp

I tried to create static lib from them, called “libosm.a” with Makefile.

my cpp and h file work( I compiled them without Makefile), but my Makefile doesn’t work. This is the Makefile:

CC = g++
RANLIB = ranlib

LIBSRC = osm.cpp
LIBOBJ=$(LIBSRC:.cpp=.o)

CFLAGS = -Wall -g -O0
LOADLIBES = -L./

OSMLIB = libosm.a
TARGETS = $(OSMLIB)

all: $(TARGETS)

osm.o: osm.cpp osm.h
    $(CC) -c osm.cpp -o osm.o

$(TARGETS): $(LIBOBJ)
    ar rcs $(OSMLIB) osm.o
    ranlib $(OSMLIB)

clean:
    rm osm.o $(TARGETS) $(OSMLIB) $(LIBOBJ)

depend:
    makedepend -- $(CFLAGS) -- $(SRC) $(LIBSRC)

and this is part of the error I’m getting:

osm.o: In function `_start':
(.text+0x0): multiple definition of `_start'
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 0 has invalid symbol index 11
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 1 has invalid symbol index 12

can anyone help?

Answer 1

I believe a make file as simple as this one will do the job

LIBSRC = osm.cpp
OSMLIB = libosm.a

CFLAGS = -Wall -g -O0
LOADLIBES = -L./

$(OSMLIB): $(LIBSRC)

just with the built-in rules of GNU make. And you really don’t want to set CC to g++ at all. If then to gcc which will pick the proper backend for you.

Note: to see the built-in rules of your make, use this:

make -pn -f /dev/null