c++ compile

 $表示系统提示符

// unique_ptr::reset example
#include <iostream>
#include <memory>

int main () {
  std::unique_ptr<int> up;  // empty

  up.reset (new int);       // takes ownership of pointer
  *up=5;
  std::cout << *up << '\n';

  up.reset (new int);       // deletes managed object, acquires new pointer，可以自动释放先前的指针，并重置为当前的指针
  *up=10;
  std::cout << *up << '\n';

  up.reset();               // deletes managed object

  return 0;
}

muhe221@muhe:~/share/work/test$ g++ -c xx.cpp
xx.cpp: In function ‘int main()’:
xx.cpp:6:3: error: ‘unique_ptr’ is not a member of ‘std’
xx.cpp:6:19: error: expected primary-expression before ‘int’
xx.cpp:6:19: error: expected ‘;’ before ‘int’
xx.cpp:8:3: error: ‘up’ was not declared in this scope
muhe221@muhe:~/share/work/test$ g++ -std=c++11 xx.cpp
cc1plus: error: unrecognized command line option ‘-std=c++11’

 出现这个编译错误的原因在g++ gcc 版本不够高。
添加源（Ubuntu）
$sudo add-apt-repository ppa:ubuntu-toolchain-r/test
$ sudo apt-get update
安装4.8版本
$ sudo apt-get install gcc-4.8

muhe221@muhe:~/code/m-rel_shep_mtk6795$ gcc --version
gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

但是我们可以找对应的参数即可-std=c++0x，所以就不用安装gcc-4.8

muhe221@muhe:~/share/work/test$ g++ -std=c++0x xx.cpp          //c++0x是一套标准，这里gcc 版本为4.6.3  不同gcc版本编译命令可能不一样
muhe221@muhe:~/share/work/test$ ./a.out
5
10
--------------------------------------------------------------------------------------

make file

 

//test.h
#include <iostream>

#ifndef TEST_H
#define TEST_H
using namespace std;

class Test {

public:
    Test() {
       cout << "Test()" << endl;
    }

/*
    static void* operator new(size_t size) throw() {
       cout << "operator new() size:" << size << endl;
       return NULL; 
    }
*/
    void print();

    ~Test() {
       cout << "~Test()" << endl;
    }
};

#endif

 

 

//test.cpp
#include "test.h"

void Test::print() {
    cout << "cout to output log" << endl;
    clog << "clog to output log" << endl;
    cerr << "cerr to output log" << endl;
}

 

//Haha.cpp
#include "test.h"
#include "Sales_item.h"
#include <memory>

unique_ptr<Test> getTest() {
    unique_ptr<Test> test(new Test);
    return test;
}

static void print() {
    Test* t = new Test();
    t->print();
    delete t;
}

int main() {
    print();

    printf("\n");
    unique_ptr<Test> test = getTest();
    test->print();
    sleep(10);
    return 1;
}

 

#Makefile
Haha: test.o Haha.o
        g++ test.o Haha.o -o Haha

test.o: test.cpp test.h
        g++ -c test.cpp

Haha.o: Haha.cpp
        g++ -c -std=c++0x Haha.cpp

clean: 
        rm -fr test.o Haha.o Haha

muhe221@muhe:~/share/work/cpp$ make clean
rm -fr test.o Haha.o Haha
muhe221@muhe:~/share/work/cpp$ make
g++ -c test.cpp
g++ -c -std=c++0x Haha.cpp
g++ test.o Haha.o -o Haha
muhe221@muhe:~/share/work/cpp$ ./Haha
Test()
cout to output log
clog to output log
cerr to output log
~Test()

Test()
cout to output log
clog to output log
cerr to output log

//10 s 后输出
~Test()

----------------------------------------------

#prepare files
CPP_SRCS:=$(shell find ./$(SRC) -name *.cpp)
这里又调用了一次shell，执行了find。这次是查找.cpp文件，然后把文件列表保存在CPP_SRCS里面
找到的文件是带着相对的路径名的，这个很有用。

OBJS:=$(CPP_SRCS:%.cpp=$(FinalOutput)%.o)
这里是替换，$(CPP_SRCS:%.cpp=$(FinalOutput)%.o)
的意思就是说，把CPP_SRCS里面，每个cpp部分结尾的字符串，.cpp部分都替换成.o，并且在前面加上$(FinalOutput)字符串