如何使用Makefile在不同目录中生成.o文件[重复]

Question

我正在使用 Makefile 来编译我的源文件并将其与 sfml 库链接。 这完美地工作。唯一的问题：它在与源文件 (.cpp) 相同的目录中生成 .o 文件（和 .exe）。我希望我的 Makefile 将它们生成为不同的文件（例如 /obj）。我怎么能这样做？

这是 Makefile ：

CXX      = g++
INCL_DIR = src/include
LIB_DIR  = src/lib
SRC      = $(wildcard *.cpp)
OBJ      = $(SRC:.cpp=.o)

all: compile link

compile:
    $(CXX) -I $(INCL_DIR) -c $(SRC)

link:
    $(CXX) $(OBJ) -o main -L$(LIB_DIR) -lsfml-graphics -lsfml-window -lsfml-system

Answer 1

这是我的一个 Makefile 的剪切和粘贴：

# This defines subdirectories. I have sources in ./src.
SRCDIR := src
OBJDIR := obj
BINDIR := bin

# Just a bunch of -I commands to the compiler.
# You probably don't need these.    
INCLUDES += -I. -I./generated -I/usr/local/include -I/usr/local/include/antlr4-runtime

# This gives options to g++. -O3 is optimization.
# The includes are from above, but you probably could ignore.
# --std=c++17 means this is C++ 17 rather than something older.
CXXFLAGS = -O3 ${INCLUDES} --std=c++17 -g ${AUTO_ARGUMENT}

# You can probably skip this.
LDFLAGS += -L/usr/local/lib

# This defines the command for building. You can probably make
# this much shorter.    
COMPILE.cc = $(CXX) $(CXXFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c

# This is a link command. You'll see I'm forcing a static link
# against a library, but of course, yo udon't need that.
${BINDIR}/wave: ${OBJECTS}
    ${CXX} ${OBJECTS} ${LDFLAGS} /usr/local/lib/libantlr4-runtime.a -o ${BINDIR}/wave

# Because sources can be in two different directories, I have
# two generic rules. This rule builds the generated source
# (output from antlr4) into obj/foo.o    
${OBJDIR}/%.o : generated/%.cpp
    $(COMPILE.cc) $(OUTPUT_OPTION) $<

# Same thing but the code i'm actually writing.
# Make already knows about $(OUTPUT_OPTION) and $< is
# the input.
${OBJDIR}/%.o : src/%.cpp
    $(COMPILE.cc) $(OUTPUT_OPTION) $<

我在 ./src 中有我的源代码，在 ./generated 中有一些生成的文件（来自 antlr4），所以我有两条规则来构建它们。

因此，您制定了一条规则（或在我的情况下，两条规则）在 ${OBJDIR} 目录中生成 .o 文件，然后在 ${BINDIR} 中生成二进制文件。