将Makefile设置为在另一个目录中构建

Question

Lets say my Makefile is located in the same directory as the sources and I want to store object files in obj/ subdirectory and the target executable in bin/ subdirectory.

src/
    main.cpp 
    test.cpp
    test.h
    /many other *.cpp files and headers/ 
    Makefile
    obj/
    bin/

The problem with my Makefile is that I cannot get the OBJECTS variable to contain a list of *.o files with the samy names as *.cpp files, but in OBJDIR subdirectory.

Currently it only works if I name all object files one by one.

CXX=g++
CXXFLAGS=-c -Wall 
LDFLAGS=
SOURCES=$(wildcard *.cpp) # very convenient wildcard
BINDIR=bin
OBJDIR=obj
OBJECTS=$(OBJDIR)/main.o $(OBJDIR)/test.o # how do I make a wildcard here?
TARGET=$(BINDIR)/my_executable

all: $(SOURCES) $(TARGET)

$(TARGET): $(OBJECTS)
    $(CXX) $(LDFLAGS) $(OBJECTS) -o $@

$(OBJECTS): $(OBJDIR)/%.o: %.cpp
    $(CXX) $(CXXFLAGS)  -c $< -o $@

clean:
    rm -rf $(OBJDIR)/$(OBJECTS) $(BINDIR)/$(TARGET)

Please help Thank you!

Answer 1

Similar question to yours already exists on this site here:

Can I compile all .cpp files in src/ to .o's in obj/, then link to binary in ./?

either way something like this should solve your problem:

OBJ_FILES := $(addprefix obj/,$(notdir $(CPP_FILES:.cpp=.o)))