ld: file was built for unsupported file format on Mac OS X

Question

I have to build a project with shared objects compiled on a other x64_86 computer. I have this error:

cc -std=c11 -Wall -Werror -Wextra -pedantic -I./include src/server.c
obj/tftp.o -o bin/server -L./lib64 -lSocketUDP -lAdresseInternet -lpthread
ld: warning: ld: warning: ignoring file ./lib64/libSocketUDP.so, file was
built for unsupported file format ( 0x7F 0x45 0x4C 0x46 0x02 0x01 0x01 0x00
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 ) which is not the architecture
being linked (x86_64): ./lib64/libSocketUDP.soignoring file
./lib64/libAdresseInternet.so, file was built for unsupported file format (
0x7F 0x45 0x4C 0x46 0x02 0x01 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
0x00 ) which is not the architecture being linked (x86_64):
./lib64/libAdresseInternet.so

The architecture of my Mac is x86_64 and shared objects were compiled on a x86_64. The compilation works on my Linux computer.

Here my Makefile:

CFLAGS = -std=c11 -Wall -Werror -Wextra -pedantic -I./include
LDLIBS = -L./lib64
LDFLAGS = -lSocketUDP -lAdresseInternet -lpthread

all: obj/tftp.o bin/server bin/client

obj/tftp.o: src/tftp.c
    mkdir -p obj
    $(CC) $(CFLAGS) -c $^ -o $@

bin/server: src/server.c obj/tftp.o
    mkdir -p bin
    $(CC) $(CFLAGS) $^ -o $@ $(LDLIBS) $(LDFLAGS)

bin/client: src/client.c obj/tftp.o
    mkdir -p bin
    $(CC) $(CFLAGS) $^ -o $@ $(LDLIBS) $(LDFLAGS)

clean:
    $(RM) -r obj

distclean:
    $(RM) -r obj bin

Thank you.

Answer 1

You cannot do that as this "other x86_64 computer" was clearly running Linux and generating ELF-format object files.

0x7F 0x45 0x4C 0x46
0x7F 'E'  'L'  'F'

OSX/iOS uses Mach-O format object files and cannot be linked against different types of object file.

You will need to compile all the code under OSX.

Answer 2

Your SocketUDP lib is probably built for Linux. Linux and OS X use different and incompatible object files, ELF vs . Mach-O.

You have to build the library on OS X as well.