Why am I not able to get handle of file?

Hello,

I've a code snippet. Please follow the comments.

Code:

---

                //Create a directory if it doesn't exist
                if ( !PathFileExists("C:\\TestDir") )
                {
                CreateDirectory("C:\\TestDir", NULL);
                }

                //Create a batch file in the directory
                CFile cfBatchFile( "C:\\TestDir\\TestBatch.bat", CFile::modeCreate| CFile::modeRead | CFile::modeWrite );

                //Write 'C:\\windows\\system32\cmd.exe" ipconfig>C:\\TestDir\\Test.txt in the batch file
                cfBatchFile.Write( "\"C:\\windows\\system32\cmd.exe\" ipconfig>C:\\TestDir\\Test.txt", MAX_PATH );

                cfBatchFile.Close();

                //ShellExecute runs "C:\\TestDir\\TestBatch.bat" and generates output for 'ipconfig' and redirects it to text file "C:\\TestDir\\Test.txt"
                if ( ShellExecute(NULL, "open", "C:\\TestDir\\TestBatch.bat", NULL, NULL, SW_HIDE) > (HINSTANCE)32)
                {
                        CFile* pcfTxt = NULL;

                        //Trying to open 'C:\\TestDir\\Test.txt' for reading BUT CRASH HAPPENS HERE (unhandled Exception)
                        pcfTxt = new CFile(_T("C:\\TestDir\\Test.txt"), CFile::modeRead | CFile::shareDenyNone);

                        INT nLogTxtLen = pcfTxt->GetLength();
                }

---

In Debug mode (without a Debug point), the crash is shown at

pcfTxt = new CFile(_T("C:\\TestDir\\Test.txt"), CFile::modeRead | CFile::shareDenyNone);

But if I place a debug point at :

pcfTxt = new CFile(_T("C:\\TestDir\\Test.txt"), CFile::modeRead | CFile::shareDenyNone);

and then continue, no crash arises.

I guess the issue is something to do with the handle of 'C:\\TestDir\\Test.txt' file.

How could I rectify this.

Is some Sleep() required to wait for the handle to be available.

Replies would be appreciated.

Thanks

When you use the debugger with a breakpoint, time passes, so maybe the shellexecute is still using/generating your textfile. You are trying to open it with shareDenyNone, but if the file is locked by someone else, shareDenyNone will probably fail. For testing purposes you could add a sleep of a few seconds between the execute and your fileopen. If this helps, it could be a locking problem.

Thanks for replying.

Yes, that's exactly the case.

But is using Sleep() mandatory ? Don't I have any other option to wait for the handle.

Thanks.

Code:

---

SHELLEXECUTEINFO stExec = {0};

stExec.cbSize = sizeof(SHELLEXECUTEINFO);
stExec.fMask = SEE_MASK_NOCLOSEPROCESS;
stExec.lpVerb = "open";
stExec.lpFile = "somefile.bat";
stExec.nShow = SW_HIDE;// or SW_SHOW
if (ShellExecuteEx (&stExec))
{ // Program running
  WaitForSingleObject (stExec.hProcess, INFINITE);
}
else
{
    // error
}
CloseHandle (stExec.hProcess);

---

This ShellExecuteEx function waits until it is done executing. After it is done you can open your textfile without any problems (I assume ;) ).