Generic makefile for C/C++ with automatic dependency generation, support for deep source file hierarchies and custom intermediate directories.

Makefile

# output binary
BIN := test

# source files
SRCS := \
    test.cpp

# files included in the tarball generated by 'make dist' (e.g. add LICENSE file)
DISTFILES := $(BIN)

# filename of the tar archive generated by 'make dist'
DISTOUTPUT := $(BIN).tar.gz

# intermediate directory for generated object files
OBJDIR := .o
# intermediate directory for generated dependency files
DEPDIR := .d

# object files, auto generated from source files
OBJS := $(patsubst %,$(OBJDIR)/%.o,$(basename $(SRCS)))
# dependency files, auto generated from source files
DEPS := $(patsubst %,$(DEPDIR)/%.d,$(basename $(SRCS)))

# compilers (at least gcc and clang) don't create the subdirectories automatically
$(shell mkdir -p $(dir $(OBJS)) >/dev/null)
$(shell mkdir -p $(dir $(DEPS)) >/dev/null)

# C compiler
CC := clang
# C++ compiler
CXX := clang++
# linker
LD := clang++
# tar
TAR := tar

# C flags
CFLAGS := -std=c11
# C++ flags
CXXFLAGS := -std=c++11
# C/C++ flags
CPPFLAGS := -g -Wall -Wextra -pedantic
# linker flags
LDFLAGS :=
# linker flags: libraries to link (e.g. -lfoo)
LDLIBS :=
# flags required for dependency generation; passed to compilers
DEPFLAGS = -MT $@ -MD -MP -MF $(DEPDIR)/$*.Td

# compile C source files
COMPILE.c = $(CC) $(DEPFLAGS) $(CFLAGS) $(CPPFLAGS) -c -o $@
# compile C++ source files
COMPILE.cc = $(CXX) $(DEPFLAGS) $(CXXFLAGS) $(CPPFLAGS) -c -o $@
# link object files to binary
LINK.o = $(LD) $(LDFLAGS) $(LDLIBS) -o $@
# precompile step
PRECOMPILE =
# postcompile step
POSTCOMPILE = mv -f $(DEPDIR)/$*.Td $(DEPDIR)/$*.d

all: $(BIN)

dist: $(DISTFILES)
	$(TAR) -cvzf $(DISTOUTPUT) $^

.PHONY: clean
clean:
	$(RM) -r $(OBJDIR) $(DEPDIR)

.PHONY: distclean
distclean: clean
	$(RM) $(BIN) $(DISTOUTPUT)

.PHONY: install
install:
	@echo no install tasks configured

.PHONY: uninstall
uninstall:
	@echo no uninstall tasks configured

.PHONY: check
check:
	@echo no tests configured

.PHONY: help
help:
	@echo available targets: all dist clean distclean install uninstall check

$(BIN): $(OBJS)
	$(LINK.o) $^

$(OBJDIR)/%.o: %.c
$(OBJDIR)/%.o: %.c $(DEPDIR)/%.d
	$(PRECOMPILE)
	$(COMPILE.c) $<
	$(POSTCOMPILE)

$(OBJDIR)/%.o: %.cpp
$(OBJDIR)/%.o: %.cpp $(DEPDIR)/%.d
	$(PRECOMPILE)
	$(COMPILE.cc) $<
	$(POSTCOMPILE)

$(OBJDIR)/%.o: %.cc
$(OBJDIR)/%.o: %.cc $(DEPDIR)/%.d
	$(PRECOMPILE)
	$(COMPILE.cc) $<
	$(POSTCOMPILE)

$(OBJDIR)/%.o: %.cxx
$(OBJDIR)/%.o: %.cxx $(DEPDIR)/%.d
	$(PRECOMPILE)
	$(COMPILE.cc) $<
	$(POSTCOMPILE)

.PRECIOUS: $(DEPDIR)/%.d
$(DEPDIR)/%.d: ;

-include $(DEPS)

test.cpp

#include <iostream>

int main() {
    std::cout << "Hello, World!\n";
    return 0;
}

@maxsupermanhd That is strange. Some of the prerequisites must have changed, otherwise make wouldn't have run the recipes a second time.
Two questions: Does this happen reproducibly on every fresh build? And does this happen when running make sequentially (i.e. without -j) as well? I tried it on a sample project of mine and it works fine with and without -j4.

Two questions: Does this happen reproducibly on every fresh build? And does this happen when running make sequentially (i.e. without -j) as well? I tried it on a sample project of mine and it works fine with and without -j4.

1. Yes, every build. But first one builds all and target works fine, second run makes no sense and just making already ready to link files.
2. With or without -j this is not affecting build (except time).
   Any help will be very useful.
   @maxtruxa

@maxsupermanhd Depending on your version of make, you can run make with the --trace option which tells you why make is running stuff.

@maxtruxa Ok, I found the main reason of this, after building target make will update objects because of .d files updated. Maybe somehow implement make depend?
Traced compile log: https://pastebin.com/aktN5rVq
Can you fix this or there is my side issue?

LDLIBS is actually not defined anywhere

@MartinZeman17 That's correct. LDLIBS is one of the predefined variables used by implicit Make rules (see here). I used LDLIBS in the linker rules as well, to mirror the behavior of implicit rules but by default there are no libs specified. To make this more obvious, I added an empty assignment to LDLIBS.

@johan-boule Yes, thank you for pointing that out. Sadly, I haven't had the time to fix that.

@maxsupermanhd I had the same problem and got the makefile to handle repeated builds by treating $(DEPDIR)/%.d as an order-only dependancy, so that the creation date of the dependancy files doesn't matter.

Note to future readers: Save yourself the trouble and just use CMake.

How do I specify a source directory? Do I have to list out all of the files that need to be compiled and then make will calculate dependencies? Or can I just tell it to "compile ./src/main.cpp" and then it will look at all of the files in ./src?