So my task is simple, I have created the makefile (New with makefiles) and I want to keep my .o files in a different folder to have a cleaner directory and allow the usage of .o files by others.
I searched and found many solution pointing to using -o $< $#
However, it is giving me that g++: cannot specify -o with -c or -S with multiple files
This is what I want to do:
$(OBJECT_PATH)/file1.o: $(SOURCE_PATH)/file2.cpp $(SOURCE_PATH)/file1.cpp
$(CC) $(CFLAGS) $(SOURCE_PATH)/file2.cpp $(SOURCE_PATH)/file1.cpp -o $#
file1.cpp has #include "file1.h", so from what I read I should include file1.cpp in the dependencies. However, now I can't export to a different directory.
Is there a solution? Or do I have the concept wrong?
Use make -d or even better remake -x to understand what commands are invoked.
Run also make -p to understand what builtin rules are used.
We cannot help you more, because we have no idea if you redefined CFLAGS.
And C++ compilation should better be done with g++ that is CXX and CXXFLAGS, e.g. with (I am extracting this from my make -p output)
LINK.cc = $(CXX) $(CXXFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH)
COMPILE.cc = $(CXX) $(CXXFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c
CXX = g++
%.o: %.cc
$(COMPILE.cc) $(OUTPUT_OPTION) $<
I strongly suggest to have CXXFLAGS= -Wall -g at least during the development phase. Learn also to use gdb and valgrind.
You could have the following in your Makefile
CXXFLAGS= -g -Wall
SOURCES=f1.cc f2.cc
SOURCE_PATH=yoursourcedir/
OBJECT_PATH=yourobjectdir/
SRCFILES=$(patsubst %.cc,$(SOURCE_PATH)/%.cc,$(SOURCES))
OBJFILES=$(patsubst %.cc,$(OBJECT_PATH)/%.o,$(SOURCES))
PROGFILE=$(OBJECT_PATH)
.PHONY: all clean
all: $(PROGFILE)
$(PROGFILE): $(OBJFILES)
$(LINK.cc) $^ $(LOADLIBES) $(LDLIBS) -o $#
$(OBJECT_PATH)/%.o: $(SOURCE_PATH)/%.cc
$(COMPILE.cc) $(OUTPUT_OPTION) $<
clean:
$(RM) $(OBJECT_PATH)/*.o $(PROGFILE)
try
$(OBJECT_PATH)/file1.o: $(SOURCE_PATH)/file2.cpp $(SOURCE_PATH)/file1.cpp
$(CC) $(CFLAGS) $^ -c $#
and check that CFLAGS doesn't include -o -c or -s flags
also read about implicit rules. it might help you to orginzie your makefile
Related
I followed this guide to build a cross compiler for Raspberry Pi ARMv7. It works fine (compiles ok hello world) but the problem is I can't use Raspberry Pi libraries such as wiringpi, sqlite etc.
This is my Makefile.
CC = /opt/cross-pi-gcc/bin/arm-linux-gnueabihf-g++
QUOTE := "
CFLAGS = -g -lwiringPi -pthread -lpthread
PROGRAM = lora
OBJDIR = obj
CPP_SRCS += \
src/main.cpp \
src/radio/sx1276/sx1276.cpp \
src/radio/radio.cpp \
OBJ_FILES += \
$(OBJDIR)/main.o \
$(OBJDIR)/sx1276.o \
$(OBJDIR)/radio.o \
all: make_dir $(OBJ_FILES)
$(CC) $(OBJ_FILES) $(CFLAGS) -o $(PROGRAM)
make_dir:
mkdir -p $(OBJDIR)
$(OBJDIR)/main.o: src/main.cpp
$(CC) $(CFLAGS) -c -o $# $<
$(OBJDIR)/service.o: src/service/service.cpp
$(CC) $(CFLAGS) -c -o $# $<
$(OBJDIR)/sx1276.o: src/radio/sx1276/sx1276.cpp
$(CC) $(CFLAGS) -c -o $# $<
$(OBJDIR)/radio.o: src/radio/radio.cpp
$(CC) $(CFLAGS) -c -o $# $<
clean:
rm $(PROGRAM)
rm -rf $(OBJDIR)
The error I'm getting:
/opt/cross-pi-gcc/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: cannot find -lwiringPi
I copied some libraries from my Pi into a folder on my home dir with this command.
rsync -vR --progress -rl --delete-after --safe-links pi#192.168.1.PI:/{lib,usr,opt/vc/lib} $HOME/raspberrypi/rootfs
Which I found it here.
But I'm not sure how to link them. Did I overlook something?
Note: The piece of code I'm trying to compile was compiling fine on Windows's cross-compiler.
I'm trying to setup a tool-chain on my Linux desktop. I'm using Manjaro.
You have to tell the linker where to look for the libraries.
You can add the flag -L$HOME/raspberrypi/rootfs/usr/lib, or wherever libwiringPi.so is located.
You have to point the compiler to the right headers as well. For that you use the -I flag. E.g. -I$HOME/raspberrypi/rootfs/usr/include. This goes in the CFLAGS of the targets that include wiringPi.h.
Also, -lwiringPi -pthread -lpthread don't belong in the CFLAGS, they are linker flags. You only need them in the target that builds PROGRAM. You could add a separate variable LDFLAGS, for example.
I would like to specify a repository for an object I generate in my makefile.
I searched for a while but only found elaborate solutions, for a list of objects, while I would like to TARGET ONE OBJECT ONLY.
(makefile is new for me, so the simpler the better)
Here is my code:
///////////////////////////////////
*definition of several directories*
*definition of CC, CFLAGS, CInclude*
cutgen:
$(CC) $(CFlags) -D__LINUX__ $(CDir)cutgen.c -o cutgen
check: cutgen cutcheck.c *list of objects here*
$(CC) $(CFlags) -I $(CHeaderDir) cutcheck.c *list of objects here* -o cutcheck
./cutcheck
cutcheck.c: cutgen test.o
./cutgen $(CDir)test.c -o cutcheck.c
test.o: util.o
$(CC) $(CFlags) -c $(CInclude) $(CDir)test.c
util.o: config.o
$(CC) $(CFlags) -c $(CInclude) $(GenDir)util.c
...
...
stubs.o:
$(CC) $(CFlags) $(CInclude) -c $(StubsDir)stubs.c
clean:
rm -f *.o *~ cutcheck* cutgen
all: check
///////////////////////////////////
Here for example, I would like to generate util.o in the Objects folder.
Any help would be appreciated, thank you in advance !
$(Objects)/util.o: config.o
$(CC) $(CFlags) -c $(CInclude) $(GenDir)util.c -o $#
(And are you sure about that prerequisite? I think $(GenDir)util.c might be better than config.o.)
I'm trying to compile a project that has multiple *.c files and *.h file when I type the following command:
$gcc -c -I ../hdr main.c gestic.c menu.c
the hdr folder is where the *.h files are located, the .o files are created but when I try to link them using the command:
$gcc -o main.o gestic.o menu.o
I see errors
gestic.c:(.text+0x..): undefined reference to functions that are declared in *.h files
$gcc -Wall -c -I../hdr -o main.o main.c
$gcc -Wall -c -I../hdr -o menu.o menu.c
$gcc -Wall -c -I../hdr -o gestic.o gestic.c
$gcc -Wall -o myprogram main.o menu.o gestic.o
Using a Makefile is very common for this task
example (untested) Makefile:
CC=gcc
CFLAGS=-Wall -I../hdr
all: myprogram
myprogram: main.o menu.o gestic.o
$(CC) -o $# $^
gestic.o: gestic.c
$(CC) $(CFLAGS) -c -o $# $<
main.o: main.c
$(CC) $(CFLAGS) -c -o $# $<
menu.o: menu.c
$(CC) $(CFLAGS) -c -o $# $<
Try:
$ gcc main.o gestic.o menu.o
-o filename: Place output in filename
Firstly header files are not included, secondly you might use the function that doesn't contain the definition.
The message undefined reference to 'function_name' implies that of all the object files you're giving to the linker, none of them has a definition for function_name. That means that either
You're not linking with *.o
*.c (as compiled) does not contain a definition for function_name -- by 'as compiled' I mean with all of the various preprocessor options you use on it.
here -Iinclude/
try,
gcc -c file.c -I<include_dir>
If you compile more files better to have makefile to create the objects of those files, link those objects along with header.
Sample makefile,
CC = gcc
CFLAGS = -Wall
INCLUDE = sample.h
OBJ = samople1.o sample2.o
%.o: %.c $(INCLUDE)
$(CC) $(CFLAGS) -c -o $# $<
go: $(OBJ)
gcc $(CFLAGS) -o $# $^
FC= ifort
FCFLAGS=-O2 -r8 -openmp -mcmodel=large -extend-source -shared-intel -I$(HOME)/usr/include
LDFLAGS=-L$(HOME)/usr/lib -lfftw3 -lm
TARGET=Project
Project: a.o b.o c.o d.o
#
all : $(TARGET)
%: %.o
$(FC) $(FCFLAGS) -o $# $^ $(LDFLAGS)
%.o: %.f90
$(FC) $(FCFLAGS) -c $<
all : $(TARGET)
clean :
rm *.o
when I studied makefile, there is no information for
#
all : $(TARGET)
and function of % and $^. I wanna check about these things. Thanks for your help.
all is a target (repeated twice in that makefile for no reason). So is clean. Targets are how make works. See Rule Example.
$^ is one of the Automatic Variables available for use in target recipes.
% is a wildcard used in some make functions and in Pattern Rules.
So I am having some issues understanding how exactly the % wildcard actually works using makefile. I have looked at static pattern rules in the GNU make man but i am still pretty confused and I feel like I have seen them do something similar to what I have below.
EXEC = a.out
CC = gcc
FLAGS = -Wall -c
$(EXEC): %.o
$(CC) -o $(EXEC) $<
%.o: %.c
$(CC) $(FLAGS) $<
clean:
rm -rf *.o
I keep getting an error that says %.o rule not defined. If someone could explain why this is wrong (probably in many ways, guessing the automatic variable part is incorrect as well) that would be appreciated !
I'm not sure what you intend, but I'm pretty sure that this rule:
$(EXEC): %.o
$(CC) -o $(EXEC) $<
doesn't do it. In this rule, '%' is not any kind of wildcard, it's just a character. So when Make tries build a.out, it goes looking for a file called %.o, can't find it, doesn't have a rule to build it (since there is no %.c and no way to build that), and gives up.
Your intention is unclear. If you want the rule to be able to build a.out from a.o (and likewise foo.out from foo.o, and bar.out from bar.o, and so on), write a pattern rule:
%.out: %.o
$(CC) -o $# $<
$(EXEC): # Make will not use a pattern rule as the default, so we need this
(Note the use of $#.) Or (to restrict it to executables in the EXEC list) a static pattern rule:
$(EXEC): %.out : %.o
$(CC) -o $# $<
If, on the other hand, you want Make to use all the source files it can find to build this executable, you must do something like this:
SOURCES = $(wildcard *.c) # make a list a.c foo.c bar.c
OBJECTS = $(patsubst %.c, %.o, $(SOURCES)) # translate it into a.o foo.o bar.o
$(EXEC): $(OBJECTS)
$(CC) -o $^ $<
Note the use of the wildcard function, and $^ which expands to the list of prerequisites, and also note that "*.o" wouldn't do you much good.
when I used to use makefiles long time ago they looked more like below. For each executable we listed the required object files explicitly.
CC = gcc
FLAGS = -Wall -c
prog1: mod1.o mod2.o
$(CC) mod1.o mod2.o -o prog1
prog2: mod1.o mod3.o
$(CC) mod1.o mod3.o -o prog2
%.o: %.c
$(CC) $(FLAGS) $<
clean:
rm -rf *.o