1 概述
编译工具有很多(make/cmake/BJam)。如果不考虑跨平台的话,还是make比较方便。使用make编译需要编写Makefile。本文编写Makefile来生成C/C++可执行程序。
2 Makefile文件命名
Makefile文件首先是一个文本文件,Linux下默认有两种命名方式:
- Makefile 这是最常用的命名方式
- makefile 这是优先级高的命名方式
在工程目录下运行make命令,make程序先找makefile,如果没有makefile再找Makefile文件。也就是说如果makefile和Makefile两个文件都存在默认使用makefile。
其实Makefile的文件名可以是任意的,例如Buildfile,可以使用下面命令编译:
bash
make -f BuildFile
本文使用make程序版本:
bash
$make --version
GNU Make 4.2.1
Built for x86_64-pc-linux-gnu
Copyright (C) 1988-2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
3 MakeFile实例
这里以CppTest库测试代码为例,代码目录结构:
bash
cpptest2.0.0$ tree
.
├── Makefile
├── cpptest
│ ├── Makefile
│ ├── inc
│ │ ├── cpptest-assert.h
│ │ ├── cpptest-collectoroutput.h
│ │ ├── cpptest-compileroutput.h
│ │ ├── cpptest-htmloutput.h
│ │ ├── cpptest-output.h
│ │ ├── cpptest-source.h
│ │ ├── cpptest-suite.h
│ │ ├── cpptest-textoutput.h
│ │ ├── cpptest-time.h
│ │ └── cpptest.h
│ └── src
│ ├── collectoroutput.cpp
│ ├── compileroutput.cpp
│ ├── config.h
│ ├── htmloutput.cpp
│ ├── missing.cpp
│ ├── missing.h
│ ├── source.cpp
│ ├── suite.cpp
│ ├── textoutput.cpp
│ ├── time.cpp
│ ├── utils.cpp
│ ├── utils.h
│ └── winconfig.h
└── test
├── Makefile
└── mytest.cpp
4 directories, 27 files
3.1 Makefile
makefile
all:
@make -C cpptest
@make -C test
clean:
@make -C cpptest clean
@make -C test clean
.PHNOY: all clean
说明:
- 根目录Makefile调用cpptest和test目录下Makefile进行编译。
3.2 cpptest/Makefile
参考上一篇文章Linux Makefile编写之静态库
3.3 test/Makefile
makefile
PROJECT_NAME ?= test
PWD := $(shell pwd)
TOP := $(PWD)/..
INCS := -I$(TOP)/cpptest/inc
SRCDIR := $(PWD)
BINDIR := $(TOP)/bin
LIBS := $(TOP)/cpptest/lib/libcpptest.a
APPNAME := $(BINDIR)/$(PROJECT_NAME)
CC ?= gcc
CXX ?= g++
CFLAGS :=
C++FLAGS := -std=c++11
LINKFLAGS :=
CSRC := $(wildcard $(SRCDIR)/*.c)
OBJS := $(patsubst %.c,%.o,$(CSRC))
CPPS := $(wildcard $(SRCDIR)/*.cpp)
CPPOBJS := $(patsubst %.cpp,%.o,$(CPPS))
all: $(OBJS) $(CPPOBJS) $(BINDIR)
$(CXX) $(OBJS) $(CPPOBJS) $(LIBS) $(LINKFLAGS) -o $(APPNAME)
$(OBJS): %.o:%.c
$(CC) -c $(CFLAGS) $(INCS) $< -o $@
$(CPPOBJS): %.o:%.cpp
$(CXX) -c $(C++FLAGS) $(INCS) $< -o $@
$(BINDIR):
@mkdir -p $(BINDIR)
.PHNOY:clean
clean:
@rm -f $(OBJS) $(CPPOBJS)
@rm -f $(APPNAME)
3.4
编译结果:
bash
make[1]: Entering directory '/home/james/git/cpptest2.0.0/cpptest'
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/utils.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/utils.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/source.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/source.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/time.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/time.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/collectoroutput.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/collectoroutput.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/textoutput.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/textoutput.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/compileroutput.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/compileroutput.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/htmloutput.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/htmloutput.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/suite.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/suite.o
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/cpptest/inc /home/james/git/cpptest2.0.0/cpptest/src/missing.cpp -o /home/james/git/cpptest2.0.0/cpptest/src/missing.o
ar -rcD /home/james/git/cpptest2.0.0/cpptest/lib/libcpptest.a /home/james/git/cpptest2.0.0/cpptest/src/utils.o /home/james/git/cpptest2.0.0/cpptest/src/source.o /home/james/git/cpptest2.0.0/cpptest/src/time.o /home/james/git/cpptest2.0.0/cpptest/src/collectoroutput.o /home/james/git/cpptest2.0.0/cpptest/src/textoutput.o /home/james/git/cpptest2.0.0/cpptest/src/compileroutput.o /home/james/git/cpptest2.0.0/cpptest/src/htmloutput.o /home/james/git/cpptest2.0.0/cpptest/src/suite.o /home/james/git/cpptest2.0.0/cpptest/src/missing.o
make[1]: Leaving directory '/home/james/git/cpptest2.0.0/cpptest'
make[1]: Entering directory '/home/james/git/cpptest2.0.0/test'
g++ -c -std=c++11 -I/home/james/git/cpptest2.0.0/test/../cpptest/inc /home/james/git/cpptest2.0.0/test/mytest.cpp -o /home/james/git/cpptest2.0.0/test/mytest.o
g++ /home/james/git/cpptest2.0.0/test/mytest.o /home/james/git/cpptest2.0.0/test/../cpptest/lib/libcpptest.a -o /home/james/git/cpptest2.0.0/test/../bin/test
make[1]: Leaving directory '/home/james/git/cpptest2.0.0/test'
说明:
- 编译生成静态库libcpptes.a文件放在cpptest/lib目录下
- 编译生成可执行程序放bin目录下
- 编译生成.o与源码在同一目录
4 代码分析
4.1 定义工程名及路径
makefile
PROJECT_NAME ?= test
PWD := $(shell pwd)
TOP := $(PWD)/..
INCS := -I$(TOP)/cpptest/inc
SRCDIR := $(PWD)
BINDIR := $(TOP)/bin
LIBS := $(TOP)/cpptest/lib/libcpptest.a
APPNAME := $(BINDIR)/$(PROJECT_NAME)
说明:
- 定义工程名
- 调用shell命令pwd获取当前路径PWD
- 利用PWD定义include/src/bin路径
- 定义依赖库名称
- 定义可执行程序名称
4.2 定义编译器及选项
bash
CC ?= gcc
CXX ?= g++
CFLAGS :=
C++FLAGS := -std=c++11
LINKFLAGS :=
说明:
- 定义C/C++编译器名称
- 定义C/C++编译选项,C++使用C++11标准。
- 定义链接选项LINKFLAGS
4.3 自动选择译源文件
CSRC := $(wildcard $(SRCDIR)/*.c)
OBJS := $(patsubst %.c,%.o,$(CSRC))
CPPS := $(wildcard $(SRCDIR)/*.cpp)
CPPOBJS := $(patsubst %.cpp,%.o,$(CPPS))
说明:
- 调用函数wildcard扫描src下所有.c/.cpp文件
- 调用函数patsubst通过源文件生成.o目标文件
4.4 编译依赖项
makefile
all: $(OBJS) $(CPPOBJS) $(BINDIR)
$(CXX) $(OBJS) $(CPPOBJS) $(LIBS) $(LINKFLAGS) -o $(APPNAME)
$(OBJS): %.o:%.c
$(CC) -c $(CFLAGS) $(INCS) $< -o $@
$(CPPOBJS): %.o:%.cpp
$(CXX) -c $(C++FLAGS) $(INCS) $< -o $@
$(BINDIR):
@mkdir -p $(BINDIR)
.PHNOY:clean
clean:
@rm -f $(OBJS) $(CPPOBJS)
@rm -f $(APPNAME)
说明:
- $(OBJS)依赖项编译.c文件为.o文件
- $(CPPOBJS)依赖项编译.cpp文件为.o文件
- $(BINDIR)依赖项创建目录bin
- all依赖项将.o文件和.a文件链接成可执行文件。
- clean依赖项删除编译生成.o和可执行文件。