Makefile reference dependencies with patsubst or wildcard?

问题

Following this question and my answer and its comments I have a doubt.

What is the proper way to reference dependencies in a Makefile?

Let me give an example considering this file:

CXX = g++
CXXFLAGS = -stdlib=libc++ -std=c++17
WARNING := -Wall -Wextra

PROJDIR   := .
SOURCEDIR := $(PROJDIR)/
SOURCES   := $(wildcard $(SOURCEDIR)/*.cpp)
OBJDIR    := $(PROJDIR)/

OBJECTS := $(patsubst $(SOURCEDIR)/%.cpp,$(OBJDIR)/%.o,$(SOURCES))
DEPENDS := $(patsubst $(SOURCEDIR)/%.cpp,$(OBJDIR)/%.d,$(SOURCES))

# .PHONY means these rules get executed even if
# files of those names exist.
.PHONY: all clean

all: main

clean:
    $(RM) $(OBJECTS) $(DEPENDS) main

        clean:
            $(RM) $(OBJECTS) $(DEPENDS) parking

# Linking the executable from the object files
main: $(OBJECTS)
    $(CXX) $(WARNING) $(CXXFLAGS) $^ -o $@


#include your dependencies
-include $(DEPENDS)

#create OBJDIR if not existin (you should not need this)
$(OBJDIR):
    mkdir -p $(OBJDIR)

$(OBJDIR)/%.o: $(SOURCEDIR)/%.cpp Makefile | $(OBJDIR)
    $(CXX) $(WARNING) $(CXXFLAGS) -MMD -MP -c $< -o $@

I can do DEPENDS := $(patsubst $(SOURCEDIR)/%.cpp,$(OBJDIR)/%.d,$(SOURCES)) but also DEPENDS := $(wildcard $(OBJDIR)/*.d): can't I?

If I delete a source file before running make clean the correspondent dependency file remains. In the second case it will be removed with the next make clean while in the first it will not. However if I do not run make clean dependencies not related to the sources might be included.

What is the best way to reference dependencies in a Makefile? Should I use two variables, one to run clean and the other for include?

来源：https://stackoverflow.com/questions/54196204/makefile-reference-dependencies-with-patsubst-or-wildcard

标签

makefile

dependencies

wildcard