我正在尝试使用处于挂起状态的 CreateProcess 创建进程并从它的标准输出中读取。对于基础，我采用了 MSDN 代码。创建进程后，我将在进程上设置作业限制（尚未实现），然后我开始在来自 STDOUT 管道的单独线程中读取。在启动线程之前，我恢复挂起的进程。结果我从 ReadFile 调用中什么也得不到，即使进程完成，它也会停止并等待数据到达。这是代码
#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_RdDup = NULL;
HANDLE g_hChildStd_OUT_Wr = NULL;
HANDLE g_hSavedStd_OUT_Wr = NULL;
HANDLE g_hInputFile = NULL;
DWORD WINAPI CreateChildProcess(LPVOID param);
void WriteToPipe(void);
DWORD WINAPI ReadFromPipe(LPVOID param);
void ErrorExit(PTSTR);
PROCESS_INFORMATION piProcInfo;
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"));
STARTUPINFO siStartInfo;
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;
//CreateThread(&saAttr,0, CreateChildProcess, &siStartInfo, 0, NULL);
CreateChildProcess(&siStartInfo);
ResumeThread(piProcInfo.hThread);
printf( "\n->Contents of child process STDOUT:\n\n", argv[1]);
//ReadFromPipe(NULL);
HANDLE thread = CreateThread(&saAttr,0, ReadFromPipe, &siStartInfo, 0, NULL);
WaitForSingleObject(thread, INFINITE);
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;
}
DWORD WINAPI CreateChildProcess(LPVOID param)
// Create a child process that uses the previously created pipes for STDIN and STDOUT.
{
TCHAR szCmdline[]=TEXT("C:\\GnuWin32\\bin\\ls.exe");
STARTUPINFO *siStartInfo = (STARTUPINFO*)param;
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.
// Create the child process.
bSuccess = CreateProcess(NULL,
szCmdline, // command line
NULL, // process security attributes
NULL, // primary thread security attributes
TRUE, // handles are inherited
CREATE_SUSPENDED | CREATE_SEPARATE_WOW_VDM | CREATE_NO_WINDOW, // creation flags
NULL, // use parent's environment
NULL, // use parent's current directory
siStartInfo, // STARTUPINFO pointer
&piProcInfo); // receives PROCESS_INFORMATION
//If resumethread is here - it works well
// 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);
}
return 0;
}
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"));
}
DWORD WINAPI ReadFromPipe(LPVOID param)
// 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;
}
return 0;
}
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);
}
如果我调用 ResumeThread(piProcInfo.hThread); 就在 CreateProcess 函数之后 - 它运行良好。但是我无论如何都需要在单独的函数中创建并在之后调用 ResumeThread 几个函数。所以，我想怎么做才能让程序在单独的线程中获得暂停进程的输出。