重定向子进程的输入和输出不起作用
Redirecting Input and Output of child process not working
我已经编写了两个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，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，也没有显示输出，而且gui应用程序似乎冻结了！
这是我的代码：
[控制台部分]：
#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部分]：
#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：
我根据Barmak Shemirani的回答更新了代码，并使用了ANSI字符集。但是writetopipe部分不起作用，在readfrompipe部分，如果在CreateProcessA中使用"/c dir"作为第二个参数，而不是"/c c:\consoleap.exe"，则它只显示输出的第一行，而不是总输出。为什么会发生这种情况？
[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;
}
我不确定重定向控制台窗口的输入和输出是否有意义。如果这是为了练习，那么我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。这一部分让人困惑，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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