[Makefile] 递归编译的Makefile的实现

转自：http://www.linuxidc.com/Linux/2017-01/139702.htm

最近写了一个递归Makefile，目的是既可以实现子模块的单独编译，也可以不做任何修改就和整个程序的整体进行无缝衔接的编译。具体的思路是借助第三方文件，将子模块编译好的.o文件的路径自动写到config.mk文件中，在总控Makfile中只需要include这个config.mk就可以。单个模块的编译只需要cd到相应目录就可以进行本模块的单独编译，整个程序的编译也只需要cd到顶层目录，分别执行make config,make,make install就可以进行编译和安装。下面这个就是顶层Makefile

CROSS_COMPILE=
#CC=/opt/arm-cross-compile/arm-2010.09/bin/arm-none-linux-gnueabi-gcc
#CC=gcc
CC=arm-linux-gnueabi-gcc
D=-DDEBUG
CFLAGS= -g -O3 $(D)

export CC CFLAGS 

INCLUDE_DIR = $(shell cd ./common/include/; pwd)
SUB_DIR= ./entry/   \
         ./sqlite/  \

NFS_DIR:=~/nfs
CORE_NAME = core
$(shell touch config.mk)
include ./config.mk 

all:$(OBJS)
    $(CC) $(CFLAGS) $^ -lpthread -L/home/jiang/nfs/usr/lib/ -lsqlite3 -o $(CORE_NAME)

config:
    @echo "OBJS+=\\" > config.mk
    @for dir in $(SUB_DIR);         \
    do                              \
        echo "\n";          \
        $(MAKE) -C $$dir ;      \
        echo "\n";              \
    done

clean:
    $(RM) ./config.mk
    @for dir in $(SUB_DIR);         \
    do                              \
        echo "\n";              \
        $(MAKE) -C $$dir clean; \
        echo "\n";              \
        done
install:
    cp $(CORE_NAME) $(NFS_DIR)

下面这个就是每一个子模块的Makfile，会把编译成功的.o文件路径添加到config.mk中

CUR_DIR=$(shell pwd)
OBJ_DIR:=$(CUR_DIR)/obj
INCLUDE_DIR= -I ./include -I ../common/include
SRC=$(wildcard ./src/*.c)

all:$(SRC)
    $(CC) $(CFLAGS) $(INCLUDE_DIR) -c $^
    mv ./*.o $(OBJ_DIR)
    echo "${OBJ_DIR}/*.o \\" >> ../config.mk
    echo "\033[44;37m $(notdir $(CUR_DIR)) done \033[0m"
clean:
    $(RM) $(OBJ_DIR)/* 

下面就是config.mk的内容，会在顶层目录中执行make config之后自动生成

OBJS+=\
/home/jiang/Documents/Documents/IntellStorage/A9_main/A9_core/entry/obj/*.o \
/home/jiang/Documents/Documents/IntellStorage/A9_main/A9_core/sqlite/obj/*.o \

为了使一个头文件的实例在整个工程中只有一份，对于接口文件，约定一律以inter_开头进行命名并且放置在自己的include目录中，下面这个脚本的作用就是扫描指定的子模块的include目录，将其中的inter_*头文件在entry模块的include中自动生成同名符号链接文件。

#|/bin/bash
#扫描指定include的文件，符合inter_*.h的文件会自动在entry/include中创建其符号链接

SHELL_DIR=$(cd $(dirname ${0});pwd)
cd ${SHELL_DIR}
SUB_INCLUDES="../camera/include ../buzzer/include ../gsm/include ../led/include ../sqlite/include ../zigbee/include"
for A_SUB_INCLUDE in ${SUB_INCLUDES}
do
    echo ${A_SUB_INCLUDE}
    (
    cd ${A_SUB_INCLUDE}
    HEADERS=$(ls ./inter*)
    for A_HEADER in ${HEADERS}
    do
        ln -s ../${A_SUB_INCLUDE}/${A_HEADER} ../../entry/include/${A_HEADER}
    done
    )
done