#include <windows.h> #include <tchar.h>#include <stdio.h> #include <strsafe.h>#define BUFSIZE 4096 HANDLE g_hChildStd_IN_Rd = NULL;HANDLE g_hChildStd_IN_Wr = NULL;HANDLE g_hChildStd_OUT_Rd = NULL;HANDLE g_hChildStd_OUT_Wr = NULL;HANDLE g_hInputFile = NULL; void CreateChildProcess(void); void WriteToPipe(void); void ReadFromPipe(void); void ErrorExit(PTSTR); int _tmain(int argc, TCHAR *argv[]) { 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) ) ErrorExit(TEXT("StdoutRd CreatePipe")); // Ensure the read handle to the pipe for STDOUT is not inherited. if ( ! SetHandleInformation(g_hChildStd_OUT_Rd, HANDLE_FLAG_INHERIT, 0) ) ErrorExit(TEXT("Stdout SetHandleInformation")); // Create a pipe for the child process's STDIN. if (! CreatePipe(&g_hChildStd_IN_Rd, &g_hChildStd_IN_Wr, &saAttr, 0)) ErrorExit(TEXT("Stdin CreatePipe")); // Ensure the write handle to the pipe for STDIN is not inherited. if ( ! SetHandleInformation(g_hChildStd_IN_Wr, HANDLE_FLAG_INHERIT, 0) ) ErrorExit(TEXT("Stdin SetHandleInformation")); // Create the child process. CreateChildProcess();// Get a handle to an input file for the parent. // This example assumes a plain text file and uses string output to verify data flow. if (argc == 1) ErrorExit(TEXT("Please specify an input file.\n")); g_hInputFile = CreateFile( argv[1], GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_READONLY, NULL); if ( g_hInputFile == INVALID_HANDLE_VALUE ) ErrorExit(TEXT("CreateFile")); // Write to the pipe that is the standard input for a child process. // Data is written to the pipe's buffers, so it is not necessary to wait// until the child process is running before writing data. WriteToPipe(); printf( "\n->Contents of %s written to child STDIN pipe.\n", argv[1]); // Read from pipe that is the standard output for child process. printf( "\n->Contents of child process STDOUT:\n\n", argv[1]); ReadFromPipe(); printf("\n->End of parent execution.\n");// The remaining open handles are cleaned up when this process terminates. // To avoid resource leaks in a larger application, close handles explicitly. return 0; } void CreateChildProcess()// Create a child process that uses the previously created pipes for STDIN and STDOUT.{ TCHAR szCmdline[]=TEXT("child"); PROCESS_INFORMATION piProcInfo; STARTUPINFO siStartInfo; 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 ) ErrorExit(TEXT("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 WriteToPipe(void) // Read from a file and write its contents to the pipe for the child's STDIN.// Stop when there is no more data. { DWORD dwRead, dwWritten; CHAR chBuf[BUFSIZE]; BOOL bSuccess = FALSE; for (;;) { bSuccess = ReadFile(g_hInputFile, chBuf, BUFSIZE, &dwRead, NULL); if ( ! bSuccess || dwRead == 0 ) break; bSuccess = WriteFile(g_hChildStd_IN_Wr, chBuf, dwRead, &dwWritten, NULL); if ( ! bSuccess ) break; } // Close the pipe handle so the child process stops reading. if ( ! CloseHandle(g_hChildStd_IN_Wr) ) ErrorExit(TEXT("StdInWr CloseHandle")); } 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 (;;) { bSuccess = ReadFile( g_hChildStd_OUT_Rd, chBuf, BUFSIZE, &dwRead, NULL); if( ! bSuccess || dwRead == 0 ) break; bSuccess = WriteFile(hParentStdOut, chBuf, dwRead, &dwWritten, NULL); if (! bSuccess ) break; } } void ErrorExit(PTSTR lpszFunction) // Format a readable error message, display a message box, // and exit from the application.{ LPVOID lpMsgBuf; LPVOID lpDisplayBuf; DWORD dw = GetLastError(); FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &lpMsgBuf, 0, NULL ); lpDisplayBuf = (LPVOID)LocalAlloc(LMEM_ZEROINIT, (lstrlen((LPCTSTR)lpMsgBuf)+lstrlen((LPCTSTR)lpszFunction)+40)*sizeof(TCHAR)); StringCchPrintf((LPTSTR)lpDisplayBuf, LocalSize(lpDisplayBuf) / sizeof(TCHAR), TEXT("%s failed with error %d: %s"), lpszFunction, dw, lpMsgBuf); MessageBox(NULL, (LPCTSTR)lpDisplayBuf, TEXT("Error"), MB_OK); LocalFree(lpMsgBuf); LocalFree(lpDisplayBuf); ExitProcess(1);}
联系客服
