将命令行进程的Stdout重定向到文件

Question

我有一个MFC应用程序，它通过CreateProcess函数向cmd发送命令。我想把stdout放到一个日志文件中。代码就像这个

    void CMainFrame::OnCompile( CString cmd )
    {
    CWaitCursor cursor;
    SECURITY_ATTRIBUTES sec;
    ZeroMemory( &sec, sizeof(sec) );
    sec.nLength = sizeof(SECURITY_ATTRIBUTES);
    sec.lpSecurityDescriptor = NULL;    
    sec.bInheritHandle = TRUE;
    HANDLE hstdoutf = CreateFile("e:\user_stdout.txt",GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,&sec,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);
    STARTUPINFO siStartupInfo;
    PROCESS_INFORMATION piProcessInfo;
    memset(&siStartupInfo, 0, sizeof(siStartupInfo));
    memset(&piProcessInfo, 0, sizeof(piProcessInfo));
    siStartupInfo.cb = sizeof(siStartupInfo);
    siStartupInfo.dwFlags = STARTF_USESHOWWINDOW  ;
    siStartupInfo.wShowWindow = SW_HIDE; 


    if (hstdoutf!=INVALID_HANDLE_VALUE) {
        siStartupInfo.hStdOutput=hstdoutf;
    }
    // Wait up to 100 seconds for the compilation process to finish
    if (!::CreateProcess(0, (char*)(cmd.GetString()), 0, 0, false,0, 0, 0,     
    &siStartupInfo, &piProcessInfo) ||
        (WaitForSingleObject(piProcessInfo.hProcess, 100000) != WAIT_OBJECT_0))
    {
        MessageBox("Fail to execute command","Test",MB_ICONERROR);
    }
    else
    {
        CloseHandle(hstdoutf);
    }
    }

---

但代码工作不正常。只创建一个空白文件。我做错了什么？请帮忙。

Answer 1

您忘记在siStartupInfo.dwFlags.中指定STARTF_USSESTHANDLES标志

更改

startupInfo.dwFlags = STARTF_USESHOWWINDOW  ;

至

startupInfo.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES ;

并更改

CreateProcess(0, (char*)(cmd.GetString()), 0, 0, false, 0, 0, 0,
    &siStartupInfo, &piProcessInfo)

至

CreateProcess(0, (char*)(cmd.GetString()), 0, 0, true, 0, 0, 0,
    &siStartupInfo, &piProcessInfo)

我建议您阅读STARTUPINFO文档的STARTF_USSESTHANDLES部分，其中有很多信息。

顺便说一句，你也应该添加

CloseProcess(piProcessInfo.hProcess)

最后。