如何处理“dir”的输出？

我编写了一个程序，它实现了一个微型 shell 来处理来自用户的命令。如果输入的命令被识别为内部命令，我的程序将执行此命令。

这些命令是作为内部函数实现的，它们的输出由另一个内部函数处理，该函数能够将文本发送到控制台和/或文件以进行记录。

如果无法识别输入的命令，我会尝试将输入的命令作为 Windows 命令外壳的一部分cmd dir执行，例如 :将执行dir命令并在控制台上打印输出。这是通过CreateProcess. 到现在为止我没有指定成员hStdError，hStdOutput并hStdInput在的STARTUPINFO参数。

我尝试实施和调整使用重定向输入和输出创建子进程的示例。

我没有使用他们对子进程的实现，而是尝试将 dir 命令的输出放入我的应用程序中：

#include "pch.h"
#include <windows.h>

#define BUFSIZE 512

HANDLE g_hChildStd_IN_Rd = NULL;
HANDLE g_hChildStd_IN_Wr = NULL;
HANDLE g_hChildStd_OUT_Rd = NULL;
HANDLE g_hChildStd_OUT_Wr = NULL;



PROCESS_INFORMATION piProcInfo;
STARTUPINFO siStartInfo;
void CreateChildProcess()
// Create a child process that uses the previously created pipes for STDIN and STDOUT.
{
    TCHAR szCmdline[] = TEXT("cmd /c dir q:\\Sicherung\\Bilder /s");
    BOOL bSuccess = FALSE;

    // Set up members of the PROCESS_INFORMATION structure. 

    ZeroMemory(&piProcInfo, sizeof(PROCESS_INFORMATION));

    // Set up members of the STARTUPINFO structure. 
    // This structure specifies the STDIN and STDOUT handles for redirection.

    ZeroMemory(&siStartInfo, sizeof(STARTUPINFO));
    siStartInfo.cb = sizeof(STARTUPINFO);
    siStartInfo.hStdError = g_hChildStd_OUT_Wr;
    siStartInfo.hStdOutput = g_hChildStd_OUT_Wr;
    siStartInfo.hStdInput = g_hChildStd_IN_Rd;
    siStartInfo.dwFlags |= STARTF_USESTDHANDLES;

    // Create the child process. 

    bSuccess = CreateProcess(NULL,
        szCmdline,     // command line 
        NULL,          // process security attributes 
        NULL,          // primary thread security attributes 
        TRUE,          // handles are inherited 
        0,             // creation flags 
        NULL,          // use parent's environment 
        NULL,          // use parent's current directory 
        &siStartInfo,  // STARTUPINFO pointer 
        &piProcInfo);  // receives PROCESS_INFORMATION 

     // If an error occurs, exit the application. 
    if (!bSuccess)
        return; // ErrorExit(("CreateProcess"));
    else
    {
        // Close handles to the child process and its primary thread.
        // Some applications might keep these handles to monitor the status
        // of the child process, for example. 

        //CloseHandle(piProcInfo.hProcess);
        //CloseHandle(piProcInfo.hThread);
    }
}
void ReadFromPipe(void)
// Read output from the child process's pipe for STDOUT
// and write to the parent process's pipe for STDOUT. 
// Stop when there is no more data. 
{
    DWORD dwRead, dwWritten;
    CHAR chBuf[BUFSIZE];
    BOOL bSuccess = FALSE;
    HANDLE hParentStdOut = GetStdHandle(STD_OUTPUT_HANDLE);

    for (;;)
    {
        DWORD objectstat = WAIT_TIMEOUT;
        //do
        //{
        //  objectstat = WaitForSingleObject(piProcInfo.hProcess, 0);
        //} while (objectstat != WAIT_OBJECT_0);
        memset(&chBuf[0], 0x00, BUFSIZE);
        bSuccess = ReadFile(g_hChildStd_OUT_Rd, chBuf, BUFSIZE, &dwRead, NULL);
        if (!bSuccess)
            break;

        bSuccess = WriteFile(hParentStdOut, chBuf,
            dwRead, &dwWritten, NULL);
        if (!bSuccess) 
            break;
        if (dwRead == 0)
            break;
    }
}
int main()
{
    SECURITY_ATTRIBUTES saAttr;

    printf("\n->Start of parent execution.\n");

    // Set the bInheritHandle flag so pipe handles are inherited. 

    saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
    saAttr.bInheritHandle = TRUE;
    saAttr.lpSecurityDescriptor = NULL;

    // Create a pipe for the child process's STDOUT. 
    if (!CreatePipe(&g_hChildStd_OUT_Rd, &g_hChildStd_OUT_Wr, &saAttr, 0))
        return -1;// ErrorExit("StdoutRd CreatePipe");

    // Ensure the read handle to the pipe for STDOUT is not inherited.

    if (!SetHandleInformation(g_hChildStd_OUT_Rd, HANDLE_FLAG_INHERIT, 0))
        return -2;// ErrorExit(("Stdout SetHandleInformation"));

    // Create a pipe for the child process's STDIN. 

    if (!CreatePipe(&g_hChildStd_IN_Rd, &g_hChildStd_IN_Wr, &saAttr, 0))
        return -3 ;// ErrorExit(("Stdin CreatePipe"));

    // Ensure the write handle to the pipe for STDIN is not inherited. 

    if (!SetHandleInformation(g_hChildStd_IN_Wr, HANDLE_FLAG_INHERIT, 0))
        return -4;// ErrorExit(("Stdin SetHandleInformation"));

    // Create the child process. 
    CreateChildProcess();
    ReadFromPipe();
    CloseHandle(piProcInfo.hProcess);
    CloseHandle(piProcInfo.hThread);
    return 0;
}

我知道，问题必须出在 ReadFile 上。我无法确定何时处理了 dir 命令的所有输出。检查dwRead0 或 forBUFSIZE不起作用。dwRead永远不会变成 0，并且它可能小于BUFSIZE，因为 dir 命令不够快。

那么，我应该如何结束管道数据的处理？