c++ pipe实现父子进程通信

1、父子进程通信pipe编程流程

-创建管道

-设置进程的输出到管道

-创建进程

-关闭管道写句柄

-读管道读句柄，把数据读到一个buffer里

2、注意事项

-读管道数据的时候，一定要关闭写句柄；

-父子进程通信时，句柄的传递多通过继承来完成，父进程允许这些句柄为子进程继承；创建子进程，是否继承的属性要设置为true；

 // pdfprintconsole.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include "pch.h"
#include <iostream>
#include <Windows.h>
#include<tchar.h>
#include <string.h>

int main()
{



    int page_index = 0;
    char currentBuff[1000] = { 0 };
    char cachFileName[1000] = { 0 };
    char printCommand[1000] = { 0 };
    char command[500] = { 0 };
    HANDLE handle = 0;
    BOOL                bTest = 0;
    SECURITY_ATTRIBUTES sa = { 0 };
    DWORD               dwNumberOfBytesRead = 0;
    CHAR szBuffer[10000] = { 0 };
    DWORD ret = 0;
    HANDLE   hPipeOutputRead = NULL;
    HANDLE    hPipeOutputWrite = NULL;
    
    STARTUPINFOA si = { 0 };
    PROCESS_INFORMATION pi = { 0 };    

    sa.bInheritHandle = TRUE; // TRUE为管道可以被子进程所继承  
    sa.lpSecurityDescriptor = NULL; // 默认为NULL
    sa.nLength = sizeof(SECURITY_ATTRIBUTES);
    // Create pipe for standard output redirection.
    CreatePipe(&hPipeOutputRead,  // read handle
        &hPipeOutputWrite, // write handle
        &sa,      // security attributes
        0      // number of bytes reserved for pipe - 0 default
    );
    // Make child process use hPipeOutputWrite as standard out,
        // and make sure it does not show on screen.
    si.cb = sizeof(si);
    si.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES;
    si.wShowWindow = SW_HIDE;
    //si.hStdInput = hPipeInputRead;
    si.hStdOutput = hPipeOutputWrite;
    si.hStdError = hPipeOutputWrite;
    //strcpy_s(command, " -printer "FX DocuCentre S2011" -paper 9 -printermargins C:\Users\QJ\Desktop\f3044688ce88a4b0a78c16ba85076570-5378-0010-0.png");
    strcpy_s(command," -printer "FX DocuCentre S2011" -listpapers");
    //一共执行三次
    for (int i = 0; i < 3; i++)
    {

        if (!CreateProcessA("C:\Users\QJ\source\repos\WindowsFormsApp1\x64\Debug\pdfprint.exe", command, NULL, NULL, TRUE, NULL, NULL, NULL, &si, &pi))
        {
            //AfxMessageBox("缺失pdfprint.exe文件",0,0);        
            break;
        }
        else
        {
            HANDLE hProcess = pi.hProcess;
            //等待进程退出    //CloseHandle(hPipeOutputRead);
            while (WaitForSingleObject(hProcess, INFINITE) != WAIT_OBJECT_0);
            GetExitCodeProcess(hProcess, &ret);
            //如果ret!=0,异常退出；

            //
            CloseHandle(hPipeOutputWrite);
            while (true)
            {
                bTest = ReadFile(
                    hPipeOutputRead,      // handle of the read end of our pipe
                    &szBuffer,            // address of buffer that receives data
                    sizeof(szBuffer),                  // number of bytes to read
                    &dwNumberOfBytesRead, // address of number of bytes read
                    NULL                  // non-overlapped.
                );
            
                if (!bTest)
                {
                    break;
                }
                // do something with data.
                szBuffer[dwNumberOfBytesRead] = 0;  // null terminate
            }
            if (!ret)
            {
                printf("123%s456
btest:%d
", szBuffer, bTest);
                CloseHandle(hProcess);            
                CloseHandle(hPipeOutputRead);
                break;
            }




        }
    }
    //std::cout << "Hello World!
"; 
    system("pause");
}