转帖：一辉的文章
在Linux下做开发难免要接触makefile，整个项目的构建都依赖于它。100个developer有100种makefile的写法，在一个较大的项目中，各种各样的makefile无论在开发、后期维护还是整个系统的持续集成都是一个负担。
有幸参与重构一个遗留系统的makefile，以下是一些心得和一个makefile模板。
重构目的：
1.清晰易懂、容易维护
2.方便系统的持续集成
重构原则：
1.子模块makefile模板化
2.外部依赖、通用宏定义集中化
3.中间和最终输出集中，便于系统构建
下面是总结出的一个makefile模板，我在日常的开发中都用它，其中加入了详细的注释。
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#Get the ROOT_PATH which common files located, assuming this makefile located in $(ROOT_PATH)/src/sub_module
ROOT_PATH = $(shell cd ../..; pwd)
#Where define the path of third party modules
include $(ROOT_PATH)/path
#Where define common macros such as CC=gcc, CXX=g++ and so on
include $(ROOT_PATH)/common
#Set target output path and the path of intermidiate object
#The path macros should include in $(ROOT_PATH)/path
OUT_PATH = $(OUTPUT_PATH)/submodule
OBJ_PATH = $(TMPOBJ_PATH)/submodule
TARGET = $(OUT_PATH)/targe
#If the targe is share object then set corresponding flags
#which should define in $(ROOT_PATH)/common
CFLAGS += $(CFLAGS_SO)
LDFLAGS += $(LDFLAGS_SO)
#Custom Predefines
CFLAGS += -DXXXXXXXX
CFLAGS += -DYYYYYYYY
#Dependent header files
#The path macros should include in $(ROOT_PATH)/path
CFLAGS += -I. \
-I$(XXXX_INC) \
-I$(YYYY_INC) \
-I$(ZZZZ_INC)
#Dependent libraries
#The path macros should include in $(ROOT_PATH)/path
LDFLAGS += -L$(XXXX_LIB) -lxxxx \
-L$(YYYY_LIB) -lyyyy
#Set CPP source directory
CPP_SRCDIR = .
#Or set specific CPP Source files
ADDITIONAL_CPP_SOURCES = \
$(PATH_A)/a.cpp \
$(PATH_B)/b.cpp
#Traverse every directory in $(CPP_SRCDIR), and find every cpp file
CPP_SOURCES = $(foreach d,$(CPP_SRCDIR),$(wildcard $(d)/*.cpp) ) $(ADDITIONAL_CPP_SOURCES)
#Traverse every cpp file in $(CPP_SOURCES) and get corresponding object file(.
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include ".\sqlite3_lib\sqlite3.h"
static int _callback_exec(void * notused,int argc, char ** argv, char ** aszColName)
{
int i;
for ( i=0; i<argc; i++ )
......
