一步一步写一个简单通用的makefile(四)--写一个通用的makefile编译android可执行文件

通常要把我们自己的的代码编译成在android里面编译的可执行文件，我们通常是建一个文件夹

.
├── Android.mk
├── Application.mk
├── convolve.cl
├── convolve_cl.cpp
├── convolve_cl.cpp~
├── inter_ocl
│   └── opencl
│       ├── CL
│       │   ├── cl_ext.h
│       │   ├── cl.h
│       │   ├── cl_platform.h
│       │   └── opencl.h
│       ├── clew.c
│       ├── clew.h
│       ├── ocl_wrapper.c
│       └── ocl_wrapper.h
└── mylog.h

类似这样，里面有android.mk 文件，然后进入到这个文件夹执行ndk-build,生成文件如下：

[armeabi-v7a] Install        : convolve-ocl => libs/armeabi-v7a/convolve-ocl
[armeabi-v7a] Install        : libstlport_shared.so => libs/armeabi-v7a/libstlport_shared.so

但是今天我们要修改上一章的模板makefile来编译可以在android中执行的可执行文件。

首先我们还是用之前的三个文件hellomake.c, hellofunc.c, hellofunc.h,文件树如下：

.
├── makefile
├── makefile1
└── src
    ├── hellofunc.c
    ├── hellofunc.h
    └── hellomake.c

因为要用到android的交叉编译器，所以不能用gcc，另外寻找头文件的系统路径也不一样，寻找库的路径也和linux原本的不同，所以 -I 和 -L的路径也需要修改

修改之后的makefile如下：

#Hellomake
#Magnum， 2014-10-19
# 指令编译器和选项
TOOLCHAINS_ROOT=$(NDK_HOME)/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/
TOOLCHAINS_PREFIX=$(TOOLCHAINS_ROOT)/bin/arm-linux-androideabi
TOOLCHAINS_INCLUDE=$(TOOLCHAINS_ROOT)/lib/gcc/arm-linux-androideabi/4.8/include-fixed

PLATFORM_ROOT=$(NDK_HOME)/platforms/android-17/arch-arm
NDKINC=$(PLATFORM_ROOT)/usr/include
NDKLIB=$(PLATFORM_ROOT)/usr/lib

CC=$(TOOLCHAINS_PREFIX)-gcc
CFLAGS=-Wall
# 需要链接库的库名，比如libm.a，就是-lm,需要去掉前面的lib和后面的.a
LIBS=-lm
# 设置默认搜索头文件的路径，优先是这个，然后是系统路径
IncludeDir = -I./include/ -I$(NDKINC)
# 需要链接的库的路径
LinkDir = -L$(NDKINC)
OBJ_DIR = ./obj
BIN_DIR = ./bin

#PROJECT_TOP_DIR设置成pwd 或者"./"都行
PROJECT_TOP_DIR=.#$(shell pwd)#$(shell cd ../; pwd)
PROJECT_BIN_DIR=$(PROJECT_TOP_DIR)/bin
PROJECT_SRC_DIR=$(PROJECT_TOP_DIR)/src
PROJECT_LIB_DIR=$(PROJECT_TOP_DIR)/lib
PROJECT_OBJ_DIR=$(PROJECT_TOP_DIR)/objs
MKDIR := mkdir -p

# 目标文件
EXE_NAME=hellomake
TARGET=$(BIN_DIR)/$(EXE_NAME)

#源文件的文件类型
FILE_TYPE=c
src=$(wildcard $(PROJECT_SRC_DIR)/*.$(FILE_TYPE))
dir= $(notdir $(src))
PROJECT_OBJ= $(patsubst %.$(FILE_TYPE),%.o,$(dir) )
PROJECT_ALL_OBJS= $(addprefix $(PROJECT_OBJ_DIR)/, $(PROJECT_OBJ))

all: chdir $(TARGET)

$(TARGET): $(PROJECT_ALL_OBJS)
$(CC) $(CFLAGS) -o $@ $^ $(LinkDir) $(LIBS)

chdir:
@if test ! -d $(PROJECT_OBJ_DIR) ;
then
mkdir $(PROJECT_OBJ_DIR) ;
fi

@if test ! -d $(PROJECT_BIN_DIR) ;
then
mkdir $(PROJECT_BIN_DIR) ;
fi

.PHONY : clean
clean:
-rm -rf $(PROJECT_BIN_DIR) $(PROJECT_OBJ_DIR)

$(PROJECT_OBJ_DIR)/%.o:$(PROJECT_SRC_DIR)/%.$(FILE_TYPE)
$(CC) $(CFLAGS) -o $@ -c $< $(IncludeDir)

执行make, 报错：

/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64//bin/arm-linux-androideabi-gcc -Wall  -o objs/hellofunc.o -c src/hellofunc.c -I./include/ -I/home/magnum/work-environment/android-ndk-r9d/platforms/android-17/arch-arm/usr/include
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64//bin/arm-linux-androideabi-gcc -Wall  -o objs/hellomake.o -c src/hellomake.c -I./include/ -I/home/magnum/work-environment/android-ndk-r9d/platforms/android-17/arch-arm/usr/include
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64//bin/arm-linux-androideabi-gcc -Wall  -o bin/hellomake objs/hellofunc.o objs/hellomake.o -L/home/magnum/work-environment/android-ndk-r9d/platforms/android-17/arch-arm/usr/include -lm  
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.8/../../../../arm-linux-androideabi/bin/ld: error: cannot open crtbegin_dynamic.o: No such file or directory
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.8/../../../../arm-linux-androideabi/bin/ld: error: cannot open crtend_android.o: No such file or directory
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.8/../../../../arm-linux-androideabi/bin/ld: error: cannot find -lm
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.8/../../../../arm-linux-androideabi/bin/ld: error: cannot find -lc
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.8/../../../../arm-linux-androideabi/bin/ld: error: cannot find -ldl
objs/hellofunc.o:hellofunc.c:function myPrintHelloMake: error: undefined reference to 'puts'
objs/hellomake.o:hellomake.c:function main: error: undefined reference to 'log'
objs/hellomake.o:hellomake.c:function main: error: undefined reference to 'printf'
collect2: error: ld returned 1 exit status
make: *** [bin/hellomake] Error 1

进入到objs目录，发现.o文件生成成功，所以问题应该是出现在链接的时候。

crtbegin_dynamic.o: No such file or directory  和

crtend_android.o: No such file or directory 错误，

需要修改：

CFLAGS=-Wall -nostdlib . 然后执行make，错误只剩下：

/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64//bin/arm-linux-androideabi-gcc -Wall -nostdlib  -o bin/hellomake objs/hellofunc.o objs/hellomake.o -L/home/magnum/work-environment/android-ndk-r9d/platforms/android-17/arch-arm/usr/include -lm  
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.8/../../../../arm-linux-androideabi/bin/ld: error: cannot find -lm
objs/hellofunc.o:hellofunc.c:function myPrintHelloMake: error: undefined reference to 'puts'
objs/hellomake.o:hellomake.c:function main: error: undefined reference to 'log'
objs/hellomake.o:hellomake.c:function main: error: undefined reference to 'printf'
collect2: error: ld returned 1 exit status
make: *** [bin/hellomake] Error 1

不好意思，这个是因为

LinkDir = -L$(NDKINC), 这里复制后并没有修改，应该是LinkDir = -L$(NDKLIB)，这个可以解决然后

undefined reference to 'log'

执行make，还是有一个错误：

/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64//bin/arm-linux-androideabi-gcc -Wall -nostdlib  -o objs/hellofunc.o -c src/hellofunc.c -I./include/ -I/home/magnum/work-environment/android-ndk-r9d/platforms/android-17/arch-arm/usr/include
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64//bin/arm-linux-androideabi-gcc -Wall -nostdlib  -o objs/hellomake.o -c src/hellomake.c -I./include/ -I/home/magnum/work-environment/android-ndk-r9d/platforms/android-17/arch-arm/usr/include
/home/magnum/work-environment/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64//bin/arm-linux-androideabi-gcc -Wall -nostdlib  -o bin/hellomake objs/hellofunc.o objs/hellomake.o -L/home/magnum/work-environment/android-ndk-r9d/platforms/android-17/arch-arm/usr/lib -lm -ldl  
objs/hellofunc.o:hellofunc.c:function myPrintHelloMake: error: undefined reference to 'puts'
objs/hellomake.o:hellomake.c:function main: error: undefined reference to 'printf'

修改LIBS=-lm 更改为：LIBS=-lm -lc 再次执行make, 编译成功，

adb push ./bin/hellomake /data/local/tmp;

然后执行：

adb shell /data/local/tmp/hellomake, 奇怪没有任何输出，需要修改：

PROJECT_ALL_OBJS+=$(NDKLIB)/crtbegin_dynamic.o
PROJECT_ALL_OBJS+=$(NDKLIB)/crtend_android.o

然后从新编译，push,执行得到：

Hello makefiles!
Value:2.708050

好啦，完成

最后的makefile是：