重定向子进程的输入和输出不起作用

时间：2016-01-14 08:32:23

标签： c++ windows user-interface winapi process

我编写了两个c ++应用程序，一个是控制台，另一个是gui。 我希望gui应用程序启动控制台应用程序并在其上插入输入并重定向输出和错误并在文本框中显示它们。

按下运行按钮后，我的代码在gui应用程序中不起作用，并且没有显示输出，似乎gui app冻结了！

这是我的代码：

[console part]：

#include <iostream>
using namespace std;

int main()
{
int pass;
//cout << "welcome message from cpp app ..." << endl;
cout << "please enter pass => ";
cin >> pass;
if (pass==12345)
    cout << "ok!" << endl;
else
    cout << "oops!" << endl;
//system("pause");
return 0;
}

[gui part]：

#include <windows.h>
#include <CommCtrl.h>

#define TEXTBOX1 100
#define BUTTON1 101

HWND htbx = nullptr;
HANDLE hChildStd_IN_Rd = nullptr;
HANDLE hChildStd_IN_Wr = nullptr;
HANDLE hChildStd_OUT_Rd = nullptr;
HANDLE hChildStd_OUT_Wr = nullptr;

int MessageLoop();

void ShowError()
{
    LPVOID lpMsgBuf;
    DWORD dw = GetLastError();
    DWORD flags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |FORMAT_MESSAGE_IGNORE_INSERTS;
    FormatMessage(flags, nullptr, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), LPWSTR(&lpMsgBuf), 0, nullptr);
    MessageBox(nullptr, LPCWSTR(lpMsgBuf), L"error", MB_OK);
    LocalFree(lpMsgBuf);
}
void WriteToPipe(LPCWSTR Commands2Write) 
{
    DWORD dwWritten;
    bool bSuccess = false;
    bSuccess = WriteFile(hChildStd_IN_Wr, Commands2Write, sizeof(Commands2Write), &dwWritten, nullptr);
    if (!bSuccess)
        ShowError();
    if (!CloseHandle(hChildStd_IN_Wr))
        ShowError();
}
void ReadFromPipe()
{
    DWORD dwRead;
    LPVOID lpDataBuf[4096];

    if (hChildStd_OUT_Rd==INVALID_HANDLE_VALUE)
    {
        MessageBox(0, L"INVALID HANDLE", L"error", MB_OK);
    }

    //bool bSuccess = false;
    /*bSuccess = ReadFile(hChildStd_OUT_Rd, lpDataBuf, 4096, &dwRead, nullptr);
    if (!bSuccess)
        ShowError();*/

    while (ReadFile(hChildStd_OUT_Rd, lpDataBuf, sizeof(lpDataBuf), &dwRead, nullptr))
    {
       SendMessage(htbx, WM_SETTEXT, 0, LPARAM(LPCWSTR(lpDataBuf)));
      // MessageBox(nullptr, LPCWSTR(lpDataBuf), L"Result", MB_OK);
    }
    LocalFree(lpDataBuf);

}
void Run()
{
    bool bSuccess = false;
    PROCESS_INFORMATION PI;
    ZeroMemory(&PI, sizeof(PI));
    STARTUPINFO SI;
    ZeroMemory(&SI, sizeof(SI));
    SI.cb = sizeof(SI);
    SI.dwFlags =  STARTF_USESTDHANDLES;
    //SI.hStdError = hChildStd_OUT_Wr;
    //SI.hStdOutput = hChildStd_OUT_Wr;
    //SI.hStdInput = hChildStd_IN_Rd;
    SI.hStdError = hChildStd_OUT_Rd;
    SI.hStdOutput = hChildStd_OUT_Rd;
    SI.hStdInput = hChildStd_IN_Wr;

    SECURITY_ATTRIBUTES SA;
    SA.nLength = sizeof(SECURITY_ATTRIBUTES);
    SA.bInheritHandle = TRUE;
    SA.lpSecurityDescriptor = nullptr;

    if (!CreatePipe(&hChildStd_OUT_Rd, &hChildStd_OUT_Wr, &SA, 0))
        ShowError();
    if (!SetHandleInformation(hChildStd_OUT_Rd, HANDLE_FLAG_INHERIT, 0))
        ShowError();
    if (!CreatePipe(&hChildStd_IN_Rd, &hChildStd_IN_Wr, &SA, 0))
        ShowError();
    if (!SetHandleInformation(hChildStd_IN_Wr, HANDLE_FLAG_INHERIT, 0))
        ShowError();
    bSuccess = CreateProcess(L"C:\\Windows\\system32\\cmd.exe",
        L" /c C:\\testa.exe", nullptr, nullptr, TRUE, 0, nullptr, nullptr, &SI, &PI);

    if (!bSuccess){ ShowError(); }
            else{CloseHandle(PI.hProcess);CloseHandle(PI.hThread);}

        WriteToPipe(L"12345");
        ReadFromPipe();
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{

    switch (Msg)
    {
    case WM_CREATE:
    {
        CreateWindowEx(0, WC_BUTTON, L"Run", WS_VISIBLE | WS_CHILD, 420, 100, 75, 35, hWnd, HMENU(BUTTON1), nullptr, nullptr);
        htbx=CreateWindowEx(0, WC_EDIT, L"", WS_VISIBLE | WS_CHILD | WS_BORDER| ES_MULTILINE, 10, 10, 400, 300, hWnd, HMENU(TEXTBOX1), nullptr, nullptr);
    }
    break;
    case WM_COMMAND:
        {
            switch (LOWORD(wParam))
            {
            case BUTTON1:
                Run();
                break;
            default:
                break;
            }
        }
        break;
    case WM_CLOSE:
        DestroyWindow(hWnd);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, Msg, wParam, lParam);
    }

    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPreviewInstance, LPSTR lpcmdline, int ncmdshow)
{
    WNDCLASSEX wndexcls;
    wndexcls.lpszClassName = L"win";
    wndexcls.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndexcls.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    wndexcls.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndexcls.hbrBackground = (HBRUSH)(COLOR_3DSHADOW + 1);
    wndexcls.lpszMenuName = NULL;
    wndexcls.style = NULL;
    wndexcls.hInstance = hInstance;
    wndexcls.cbSize = sizeof(WNDCLASSEX);
    wndexcls.cbClsExtra = 0;
    wndexcls.cbWndExtra = 0;
    wndexcls.lpfnWndProc = WndProc;
    RegisterClassEx(&wndexcls);
    HWND Win_Handle = CreateWindowEx(0, L"win", L"TestApp", WS_OVERLAPPEDWINDOW, 100, 100, 640, 380, 0, 0, hInstance, 0);
    ShowWindow(Win_Handle, SW_SHOWDEFAULT);
    UpdateWindow(Win_Handle);

    int exitcode;
    exitcode = MessageLoop();
    return exitcode;
}

int MessageLoop()
{
    MSG wnd_msg;
    while (GetMessage(&wnd_msg, NULL, 0, 0)>0)
    {
        TranslateMessage(&wnd_msg);
        DispatchMessage(&wnd_msg);
    }
    return (int)wnd_msg.wParam;
}

更新

我已根据Barmak Shemirani的回答更新了代码并使用了ANSI字符集。但是，如果你使用“/ c dir”作为CreateProcessA中的第二个参数而不是“/ c C：\ consoleapp.exe”，那么writetopipe部分不起作用，在readfrompipe部分，它只显示第一行输出而不是总产量。为什么会这样？

[更新代码]： 

#include <windows.h>
#include <CommCtrl.h>

#define TEXTBOX1 100
#define BUTTON1 101

HWND htbx = nullptr;
HANDLE out_read = NULL;
HANDLE out_write = NULL;
HANDLE in_read = NULL;
HANDLE in_write = NULL;

int MessageLoop();

void ShowError()
{
    LPVOID lpMsgBuf;
    DWORD dw = GetLastError();
    DWORD flags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |FORMAT_MESSAGE_IGNORE_INSERTS;
    FormatMessageA(flags, nullptr, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), LPSTR(&lpMsgBuf), 0, nullptr);
    MessageBoxA(nullptr, LPCSTR(lpMsgBuf), "error", MB_OK);
    LocalFree(lpMsgBuf);
}

void WriteToPipe() 
{
    DWORD writecount;
    char bufw[1024]; 
    //memset(bufw, 12345, 5);
    strncpy_s(bufw, "12345", sizeof(bufw));

    if (WriteFile(in_write, bufw, sizeof(bufw), &writecount, NULL))
    {
        if (!writecount)
        {
            ShowError();
        }

    }
    if (!CloseHandle(in_write))
        ShowError();

    LocalFree(bufw);
}
void ReadFromPipe()
{
    DWORD readCount;
    char bufr[1024];
    memset(bufr, 0, sizeof(bufr));
    if (ReadFile(out_read, bufr, sizeof(bufr), &readCount, NULL))
    {
        if (readCount)
        {
            SendMessageA(htbx, EM_SETSEL, WPARAM(-1), LPARAM(-1));
            SendMessageA(htbx, EM_REPLACESEL, 0, LPARAM(bufr));
        }
    }
    if (!CloseHandle(out_read))
        ShowError();

    LocalFree(bufr);
}
DWORD WINAPI run(LPVOID)
{
    PROCESS_INFORMATION pi{};
    STARTUPINFOA si{ sizeof STARTUPINFO };
    si.dwFlags = STARTF_USESTDHANDLES;

    { //set handles

        SECURITY_ATTRIBUTES secAttr;
        secAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
        secAttr.bInheritHandle = TRUE;
        secAttr.lpSecurityDescriptor = nullptr;

        if (!CreatePipe(&out_read, &out_write, &secAttr, 0)) ShowError();
        if (!SetHandleInformation(out_read, HANDLE_FLAG_INHERIT, 0)) ShowError();
        if (!CreatePipe(&in_read, &in_write, &secAttr, 0)) ShowError();
        if (!SetHandleInformation(in_write, HANDLE_FLAG_INHERIT, 0)) ShowError();

        si.hStdOutput = out_write;
        si.hStdError = out_write;
        si.hStdInput = in_read;
        si.dwFlags |= STARTF_USESTDHANDLES;
    }

    if (!CreateProcessA("C:\\Windows\\system32\\cmd.exe",
        "/c C:\\consoleapp.exe", 0, 0, TRUE, 0, 0, 0, &si, &pi))
        ShowError();

    while (pi.hProcess && WaitForSingleObject(pi.hProcess, 25) == WAIT_TIMEOUT)
    {
        if (out_read == INVALID_HANDLE_VALUE)
            ShowError();
        if (in_write == INVALID_HANDLE_VALUE)
            ShowError();

        WriteToPipe();
        ReadFromPipe();
    }

    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);

    return 0;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
    switch (Msg)
    {
    case WM_CREATE:
    {
        CreateWindowExA(0, WC_BUTTONA, "Run", WS_VISIBLE | WS_CHILD, 420, 100, 75, 35, hWnd, HMENU(BUTTON1), nullptr, nullptr);
        htbx=CreateWindowExA(0, WC_EDITA, "", WS_VISIBLE | WS_CHILD | WS_BORDER| ES_MULTILINE, 10, 10, 400, 300, hWnd, HMENU(TEXTBOX1), nullptr, nullptr);
    }
    break;
    case WM_COMMAND:
        {
            switch (LOWORD(wParam))
            {
            case BUTTON1:
                //Run();
                CreateThread(NULL, 0, run, 0, 0, NULL);
                break;
            default:
                break;
            }
        }
        break;
    case WM_CLOSE:
        DestroyWindow(hWnd);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, Msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPreviewInstance, LPSTR lpcmdline, int ncmdshow)
{
    WNDCLASSEXA wndexcls;
    wndexcls.lpszClassName = "win";
    wndexcls.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndexcls.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    wndexcls.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndexcls.hbrBackground = (HBRUSH)(COLOR_3DSHADOW + 1);
    wndexcls.lpszMenuName = NULL;
    wndexcls.style = NULL;
    wndexcls.hInstance = hInstance;
    wndexcls.cbSize = sizeof(WNDCLASSEX);
    wndexcls.cbClsExtra = 0;
    wndexcls.cbWndExtra = 0;
    wndexcls.lpfnWndProc = WndProc;
    RegisterClassExA(&wndexcls);
    HWND Win_Handle = CreateWindowExA(0, "win", "TestApp", WS_OVERLAPPEDWINDOW, 100, 100, 640, 380, 0, 0, hInstance, 0);
    ShowWindow(Win_Handle, SW_SHOWDEFAULT);
    UpdateWindow(Win_Handle);
    int exitcode;
    exitcode = MessageLoop();
    return exitcode;
}

int MessageLoop()
{
    MSG wnd_msg;
    while (GetMessage(&wnd_msg, NULL, 0, 0)>0)
    {
        TranslateMessage(&wnd_msg);
        DispatchMessage(&wnd_msg);
    }
    return (int)wnd_msg.wParam;
}

1 个答案:

答案 0 :(得分：1)

我不确定重定向控制台窗口的输入和输出是否有意义。如果这是出于锻炼目的，那么我已经展示了一个更简单的例子来重定向控制台的输出。

控制台程序似乎是ANSI，而Windows程序是UNICODE。这部分令人困惑，你必须在某些地方使用ANSI API。 

DWORD WINAPI run(LPVOID)
{
    HANDLE out_read = NULL;
    HANDLE out_write = NULL;

    PROCESS_INFORMATION pi{};
    STARTUPINFO si{ sizeof STARTUPINFO };
    si.dwFlags = STARTF_USESTDHANDLES;

    { //set handles

        SECURITY_ATTRIBUTES secAttr;
        secAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
        secAttr.bInheritHandle = TRUE;
        secAttr.lpSecurityDescriptor = nullptr;

        if (!CreatePipe(&out_read, &out_write, &secAttr, 0)) error();
        if (!SetHandleInformation(out_read, HANDLE_FLAG_INHERIT, 0)) error();

        si.hStdOutput = out_write;
        si.dwFlags |= STARTF_USESTDHANDLES;
    }

    if (!CreateProcess(L"consoleProgram.exe", 0, 0, 0, TRUE, 0, 0, 0, &si, &pi))
        error();

    while (pi.hProcess && WaitForSingleObject(pi.hProcess, 25) == WAIT_TIMEOUT)
    {
        if (out_read == INVALID_HANDLE_VALUE)
            break;

        DWORD readCount;
        char buf[1024];
        memset(buf, 0, sizeof buf);
        if (ReadFile(out_read, buf, sizeof(buf), &readCount, NULL))
        {
            if (readCount)
            {
                SendMessageA(hedit, EM_SETSEL, WPARAM(-1), LPARAM(-1));
                SendMessageA(hedit, EM_REPLACESEL, 0, (LPARAM)buf);
            }
        }
    }

    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);

    return 0;
}

LRESULT CALLBACK WndProc(...)
{
    ...
    case WM_COMMAND:
        switch (LOWORD(wParam))
            case BUTTON1:
                CreateThread(NULL, 0, run, 0, 0, NULL);
            ...
}
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