将创建进程的API-posix_spawn封装成一个进程类

将创建进程的API封装成一个进程类，用该类生成一个对象，则创建了一个进程；

主要API函数为：

 #include <spawn.h>
int posix_spawn(pid_t *restrict pid, const char *restrict path,
              const posix_spawn_file_actions_t *file_actions,
              const posix_spawnattr_t *restrict attrp,
              char *const argv[restrict], char *const envp[restrict]);
#include <sys/types.h>
#include <sys/wait.h>
pid_t wait(int *status);

       #include <spawn.h>

       int posix_spawn_file_actions_destroy(posix_spawn_file_actions_t *
              file_actions);
       int posix_spawn_file_actions_init(posix_spawn_file_actions_t *
              file_actions);

       #include <spawn.h>

       int posix_spawnattr_destroy(posix_spawnattr_t *attr);
       int posix_spawnattr_init(posix_spawnattr_t *attr);

MyProcess.h

/*************************************************************************
	> File Name: MyProcess.h
	> Author: 
	> Mail: 
	> Created Time: 2015年12月14日 星期一 20时13分03秒
 ************************************************************************/

#ifndef _MYPROCESS_H
#define _MYPROCESS_H
#include <iostream>
#include <spawn.h>
#include <string>
#include <sys/wait.h>

using std::string;

class MyProcess{
    public:
        MyProcess(string path, char **av, char **ep);
        MyProcess(string path, char **av, char **ep, posix_spawn_file_actions_t psfa, posix_spawnattr_t attr);
        void run();
        void pwait(int *x);
    private:
        pid_t pid;
        posix_spawn_file_actions_t file_actions;
        posix_spawnattr_t attrp;
        char **argv;
        char **envp;
        string ProgramPath;
};
#endif

MyProcess.cpp

/*************************************************************************
	> File Name: MyProcess.cpp
	> Author: 
	> Mail: 
	> Created Time: 2015年12月14日 星期一 20时19分58秒
 ************************************************************************/

#include "MyProcess.h"
using namespace std;

MyProcess::MyProcess(string path, char **av, char **ep)
{
    ProgramPath = path;
    argv = av;
    envp = ep;
    posix_spawn_file_actions_init(&file_actions);
    posix_spawnattr_init(&attrp);
}

MyProcess::MyProcess(string path, char **av, char **ep, posix_spawn_file_actions_t psfa, posix_spawnattr_t attr)
{
    ProgramPath = path;
    argv = av;
    envp = ep;
    file_actions = psfa;
    attrp = attr;

    posix_spawn_file_actions_init(&file_actions);
    posix_spawnattr_init(&attrp);
}

void MyProcess::run()
{
    posix_spawn(&pid, ProgramPath.c_str(), &file_actions, &attrp, argv, envp);
}

void MyProcess::pwait(int *x)
{
    wait(x);
}

main.cpp

/*************************************************************************
	> File Name: main.cpp
	> Author: 
	> Mail: 
	> Created Time: 2015年12月14日 星期一 20时04分46秒
 ************************************************************************/

#include "MyProcess.h"
#include <cstdlib>
using namespace std;

#define PROCESSNUM 2

int main(int argc, char *argv[])
{
    int wait_val[2];

    if (argc < 2){
        cout << "the argc is less than 3" << endl;
        exit(-1);
    }

    MyProcess child1("ls", argv, NULL);
    MyProcess child2("/bin/ps", argv, NULL);
    
    child1.run();
    child2.run();
    
    child1.pwait(&wait_val[0]);
    child1.pwait(&wait_val[1]);
   
    cout << "child1.pwait is " << wait_val[0] << endl;
    cout << "child2.pwait is " << wait_val[1] << endl;

    exit(0);
}

下图才是程序的运行结果：（将下面的运行结果与上图比较，证明程序正确）