日期： 2015、4、19
目的：熟悉Makefile

项目文件结构：
============================================================================
   project --> 顶层路径
|
|    | |
            include    lib src ---> Makefile   1级
|      |    |
所需头文件    所需库   |
    |
   basic app_main.c   Makefile 2级 ---> 主逻辑模块子模块basic
   |
|
   comm io Makefile 3级 --->把目标下所有的静态库文件，编译生成动态库并复制到project/lib目录
|
   io.c   Makefile    4级--> 编译目录下所有文件,并生成.a文件
============================================================================

1级Makefile:
===========================================================

点击(此处)折叠或打开

SUBDIRS := src
TARGET := app
export LIB_PATH := $(strip $(CURDIR)/lib) #export传递变量给子Make,实际上就是lib的绝对路径
export CCG := gcc #编译版本传递给子Make
all:
@list=\'$(SUBDIRS)\'; for subdir in $$list; do \\
echo \"Making all in $$list\"; \\
(cd $$subdir && make all); \\
done
.PHONY: clean
clean:
@list=\'$(SUBDIRS)\'; for subdir in $$list; do \\
$(RM) $(TARGET) *.o *.d \\
echo \"Clean in $$subdir\"; \\
(cd $$subdir && make clean); \\
done

2级Makefile:
===========================================================

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SUBDIRS := basic
TARGET := app
app_HEADERS := ../include/app
iconv_HEADERS := ../include/iconv
opencc_HEADERS := ../include/opencc
C_FLAGS += -g -Wall -O3
C_FLAGS += -MD
LIB_FLAGS := -Wl,-rpath=$(LIB_PATH) # 指定运行动态库加载路径
# -I 包含头文件
C_FLAGS += -I$(app_HEADERS) -I$(opencc_HEADERS) -I$(iconv_HEADERS)
L_FLAGS += -L$(LIB_PATH) # -L 编译加载库路径
L_FLAGS += -lbasic -lpthread -lopencc -liconv_hook
SOURCE := $(wildcard *.c) $(wildcard *.cc)
OBJS := $(patsubst %.c,%.o,$(patsubst %.cc,%.o,$(SOURCE)))
DEPS := $(patsubst %.o,%.d,$(OBJS))
all:$(TARGET)
-cp $(TARGET) ../
$(TARGET):$(OBJS)
$(CCG) $(SOURCE) $(C_FLAGS) $(LIB_FLAGS) -o $@ $(L_FLAGS)
$(OBJS):
@list=\'$(SUBDIRS)\'; for subdir in $$list; do \\
echo \"Making all in $$list\"; \\
(cd $$subdir && make all); \\
done
.PHONY: clean
clean:
@list=\'$(SUBDIRS)\'; for subdir in $$list; do \\
$(RM) $(TARGET) *.o *.d \\
echo \"Clean in $$subdir\"; \\
(cd $$subdir && make clean); \\
done

3级Makefile:
===========================================================

点击(此处)折叠或打开

SUBDIRS := time comm io log net pthread
TARGET := lib$(notdir $(CURDIR)).so
# 该模块下的所有静态库文件
SRC_OBJECT = time/libtime.a pthread/libpthread.a \\
net/libnet.a log/liblog.a io/libio.a comm/libcomm.a
all:$(TARGET)
-cp $(TARGET) ../../lib
-rm $(TARGET)
# 几个静态库文件合并成一个动态库
$(TARGET): $(SRC_OBJECT)
$(CCG) -shared -fPIC -Wl,--whole-archive $(SRC_OBJECT) \\
-Wl,--no-whole-archive -Wl,-soname -Wl,$@ -o $@
# 进入子目录
$(SRC_OBJECT):
@list=\'$(SUBDIRS)\'; for subdir in $$list; do \\
echo \"Making all in $$list\"; \\
(cd $$subdir && make all); \\
done
.PHONY: clean
clean:
@list=\'$(SUBDIRS)\'; for subdir in $$list; do \\
(cd $$subdir && make clean); \\
done

4级Makefile:
===========================================================

点击(此处)折叠或打开

TARGET := lib$(notdir $(CURDIR)).a
app_HEADERS := ../../../include/app
opencc_HEADERS := ../../../include/opencc
iconv_HEADERS := ../../../include/iconv
C_FLAGS += -fPIC -g -Wall -O3 # 几个静态库合并成动态库，需每个静态库加 -fPIC选项
C_FLAGS += -MD
C_FLAGS += -I$(app_HEADERS) -I$(opencc_HEADERS) -I$(iconv_HEADERS)
AR := ar
SOURCE := $(wildcard *.c) $(wildcard *.cc)
OBJS := $(patsubst %.c,%.o,$(patsubst %.cc,%.o,$(SOURCE)))
all:$(TARGET)
$(TARGET):$(OBJS)
$(OBJS):
$(CCG) $(C_FLAGS) -c -o $(OBJS) $(SOURCE)
$(AR) rcs $(TARGET) $(OBJS)
.PHONY: clean install
clean :
$(RM) *.a *.o *.d

总结:
1、通过export 定义变量，自动传递给子目录Makefile。 unexport停止传递。
      2、保存了$(CURDIR)当前目录路径。
      3、 -Wl,-rpath=$(LIB_PATH) 通过编译时选项，可执行程序加载动态库时，默认搜索此路径。
如无此选项，默认搜索/usr/lib /usr/local/lib
   4、 -L$(LIB_PATH) -lxxx # -L 编译库选项
5、 -I$(app_HEADERS) # 包含头文件选项
6、当需要几个静态库合并成动态库里，通过以下选项可以解决：
$(CCG) -shared -fPIC -Wl,--whole-archive $(SRC_OBJECT)  -Wl,--no-whole-archive -Wl,-soname -Wl,$@ -o $@
              且所有的静态库编译里需加入-fPIC选项。

ITPub博客

Makefile实例详解