./Header
./Srcs
./makefile

文件夹./Header/的内容是两个头文件：

那么header1.h

#ifndef HEADER1_H
#define HEADER1_H
#include <stdio.h>

void func1();

#endif

header2.h

#ifndef HEADER2_H
#define HEADER2_H
#include <stdio.h>

void func2();

#endif

在./Srcs/我有以下srcs：

src1.c

#include <header1.h>

void func1() {
   printf("func1()\n");
}

src2.c

#include <header2.h>

void func2() {
   printf("func2()\n");
}

main.c中

#include <header1.h>
#include <header2.h>

int main(int argc,char** argv) {
   func1();
   func2();
   return 0;
}

最后makefile看起来像这样：

CC=gcc
INCLUDE=-I./Header/
SRC_DIR=./Srcs/
SRC_LIST=$(addprefix $(SRC_DIR),main.c src1.c src2.c)
OBJ_LIST=$(addsuffix .o,$(basename $(SRC_LIST)))
OUTPUT=test

%.o : %.c
    $(CC) -c $< -o $@ $(INCLUDE)

all : $(OBJ_LIST)
    $(CC) -o $(OUTPUT) $(OBJ_LIST)

clean : $(OUTPUT) $(OBJ_LIST)
    rm -r $(OUTPUT) $(OBJ_LIST)

执行makefile我得到：

gcc -c Srcs/main.c -o Srcs/main.o -I./Header/
gcc -c Srcs/src1.c -o Srcs/src1.o -I./Header/
gcc -c Srcs/src2.c -o Srcs/src2.o -I./Header/
gcc -o test ./Srcs/main.o ./Srcs/src1.o ./Srcs/src2.o

具体来说,由于我使用的模式规则,所有的目标文件都是在文件夹./Srcs/中生成的,我想要实现的是将所有目标文件放入最终输出所在的目录中,我的具体例子,最终输出将在makefile所在的同一目录中.

如何编写我的makefile以实现这样的目标？

#PROjdiR is the folder where your Makefile is
PROjdiR := $(realpath $(CURDIR)/..)

#SOURCEDIR is the root folder where your sources sub-folder ares
SOURCEDIR := $(PROjdiR)/Sources

#BUILDDIR is the root folder where your objects will be
BUILDDIR := $(PROjdiR)/Build

#Dirs are the sub-folder,e.g. Sources/Folder1 and Build/Folder1
Dirs = Folder0 Folder1 Folder2

#Here we create a list of source and builder folders with full path
SOURCEDirs = $(foreach dir,$(Dirs),$(addprefix $(SOURCEDIR)/,$(dir)))
TARGETDirs = $(foreach dir,$(addprefix $(BUILDDIR)/,$(dir)))

#We allow GNU make to search for the sources in all the sources folders
VPATH = $(SOURCEDirs)

#We define a function to generate a Build/Folder1/%.o: %.c rule for each sub-folder
define generateRules
$(1)/%.o: %.c
    @echo Building $$@
    $(CC) -c  -o $$@ $$< 
endef

#Finally we generate the rule for each build folder
$(foreach targetdir,$(TARGETDirs),$(eval $(call generateRules,$(targetdir))))

或者,如果要将所有构建项放在构建目录中：

#PROjdiR is the folder where your Makefile is
PROjdiR := $(realpath $(CURDIR)/..)

#SOURCEDIR is the root folder where your sources sub-folder ares
SOURCEDIR := $(PROjdiR)/Sources

#BUILDDIR is the root folder where your objects will be
BUILDDIR := $(PROjdiR)/Build

#Dirs are the sub-folder,e.g. Sources/Folder1 and Build/Folder1
Dirs = Folder0 Folder1 Folder2

#Here we create a list of source with full path
SOURCEDirs = $(foreach dir,$(dir)))

#We allow GNU make to search for the sources in all the sources folders
VPATH = $(SOURCEDirs)

$(BUILDDIR)/%.o: %.c
    $(CC) -o $@ $<