DOS输出重定向问题。FC命令重定向失败
BOOL CDOSDlg::ExecDosCmd()

{

#define EXECDOSCMD "dir c:"

SECURITY_ATTRIBUTES sa;

HANDLE hRead,hWrite;

sa.nLength = sizeof(SECURITY_ATTRIBUTES);

sa.lpSecurityDescriptor = NULL;

sa.bInheritHandle = TRUE;

if (!CreatePipe(&hRead,&hWrite,&sa,0))

{

return FALSE;

}

char command[1024];

strcpy(command,"Cmd.exe /C ");

strcat(command,EXECDOSCMD);

STARTUPINFO si;

PROCESS_INFORMATION pi;

si.cb = sizeof(STARTUPINFO);

GetStartupInfo(&si);

si.hStdError = hWrite;

si.hStdOutput = hWrite;

si.wShowWindow = SW_HIDE;

si.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES;



if (!CreateProcess(NULL, command,NULL,NULL,TRUE,NULL,NULL,NULL,&si,&pi))

{

CloseHandle(hWrite);

CloseHandle(hRead);

return FALSE;

}

CloseHandle(hWrite);

char buffer[4096] = {0};

DWORD bytesRead;

while (true)

{

if (!ReadFile(hRead,buffer,4095,&bytesRead,NULL))

break;



AfxMessageBox(buffer); //

}

CloseHandle(hRead);

return TRUE;

}

------------------------

如果#define EXECDOSCMD "dir c:" 换成 "fc e:\\1.txt e:\\2.txt" 就在

if (!ReadFile(hRead,buffer,4095,&bytesRead,NULL))

break;

程序就跳出了？

原因是为什么？为什么dir的输出就可以正常通过管道读取 而fc的输出就不行？

已经在CMD下测试过FC命令，CMD下正常显示结果

[解决办法]

#include "stdafx.h"
#include <windows.h> 
#include <tchar.h>
#include <stdio.h> 
 
#define BUFSIZE 4096 
 
HANDLE hChildStdinRd, hChildStdinWr,  
   hChildStdoutRd, hChildStdoutWr, 
   hInputFile, hStdout;
 
BOOL CreateChildProcess(VOID); 
VOID WriteToPipe(VOID); 
VOID ReadFromPipe(VOID); 
VOID ErrorExit(LPSTR); 
 
int _tmain(int argc, TCHAR *argv[]) 
{ 
   SECURITY_ATTRIBUTES saAttr; 
   BOOL fSuccess; 
 
 
   saAttr.nLength = sizeof(SECURITY_ATTRIBUTES); 
   saAttr.bInheritHandle = TRUE; 
   saAttr.lpSecurityDescriptor = NULL; 

 
   hStdout = GetStdHandle(STD_OUTPUT_HANDLE); 
 
 
   if (! CreatePipe(&hChildStdoutRd, &hChildStdoutWr, &saAttr, 0)) 
      ErrorExit("Stdout pipe creation failed\n"); 


   SetHandleInformation( hChildStdoutRd, HANDLE_FLAG_INHERIT, 0);

 
   if (! CreatePipe(&hChildStdinRd, &hChildStdinWr, &saAttr, 0)) 
      ErrorExit("Stdin pipe creation failed\n"); 

 
   SetHandleInformation( hChildStdinWr, HANDLE_FLAG_INHERIT, 0);
 
   
   fSuccess = CreateChildProcess();
   if (! fSuccess) 
      ErrorExit("Create process failed with"); 

   ReadFromPipe(); 
 
   return 0; 
} 
 
BOOL CreateChildProcess() 
{ 
   TCHAR szCmdline[]=TEXT("fc.exe c:\\1.txt c:\\2.txt");
   PROCESS_INFORMATION piProcInfo;  
 
   STARTUPINFO siStartInfo;
   BOOL bFuncRetn = FALSE; 
 
// Set up members of the PROCESS_INFORMATION structure. 
 
   ZeroMemory( &piProcInfo, sizeof(PROCESS_INFORMATION) );
 
// Set up members of the STARTUPINFO structure. 
 
   ZeroMemory( &siStartInfo, sizeof(STARTUPINFO) );
   siStartInfo.cb = sizeof(STARTUPINFO); 
   siStartInfo.hStdError = hChildStdoutWr;
   siStartInfo.hStdOutput = hChildStdoutWr;
   siStartInfo.hStdInput = hChildStdinRd;
   siStartInfo.dwFlags 
[解决办法]
= STARTF_USESTDHANDLES;
 
// Create the child process. 
    
   bFuncRetn = 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 (bFuncRetn == 0) 
      ErrorExit("CreateProcess failed\n");
   else 
   {
      CloseHandle(piProcInfo.hProcess);
      CloseHandle(piProcInfo.hThread);
      return bFuncRetn;
   }
}
VOID ReadFromPipe(VOID) 
{ 
   DWORD dwRead, dwWritten;  
 
   CHAR chBuf[BUFSIZE]; 
   if (!CloseHandle(hChildStdoutWr)) 
      ErrorExit("Closing handle failed"); 
   for (;;) 
   { 
      if( !ReadFile( hChildStdoutRd, chBuf, BUFSIZE, &dwRead, 
         NULL) 
[解决办法]
 dwRead == 0) break; 
      if (! WriteFile(hStdout, chBuf, dwRead, &dwWritten, NULL)) 
         break; 
   } 
   int i=0;
   i++;
} 
 
VOID ErrorExit (LPSTR lpszMessage) 
{ 
   fprintf(stderr, "%s\n", lpszMessage); 
   ExitProcess(0); 
}