Question

I need to know if my program can write files to the disk (HDD, floppy, flash, CD) from where it is running. I have tried something like:

     {$I-}      Rewrite(myFile);                                             {$I+}   Result:= (IOResult = 0); 

The problem is that if the disk is read-only, Windows gives me an error message telling me that

‘appName.exe – Write Protect Error The disk cannot be written to because it is write protected. Please remove the write protection from the volume USB_BOOT in drive D:. Cancel TryAgain Continue’

How can I test for write access without raising any error/warning messages? Thanks.

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Edit:

Ok. The ‘bug’ has nothing to do with the above mentioned piece of code. I only thought that it appears there. I move the code to the read-only disk and ran it from there. The bug appears in a function called ‘CreateShortcutEx’, on this line:

 MyPFile.Save(PWChar(WFileName),False); 

MyPFile is declared like this:

var  MyObject  : IUnknown;  MySLink   : IShellLink;  MyPFile   : IPersistFile;  Directory : String;  WFileName : WideString;  MyReg     : TRegIniFile; begin  MyObject := CreateComObject(CLSID_ShellLink);  MySLink  := MyObject as IShellLink;  MyPFile  := MyObject as IPersistFile;  ..... end; 

So, why is MyPFile trying to write to the application’s drive (the one that is read-only) if the WFileName parameter is ‘C:\documents and settings\bla bla’ ?

Answer 1

Call the Windows API SetErrorMode() function to disable the error message box.

Edit:

I just tried, and this:

procedure TForm1.Button1Click(Sender: TObject); var   Str: TStream;   OldMode: Cardinal; begin   OldMode := SetErrorMode(SEM_FAILCRITICALERRORS);    try     try       Str := TFileStream.Create('z:\foo.txt', fmOpenReadWrite);       try        finally         Str.Free;       end;     except end;   finally     SetErrorMode(OldMode);   end; end; 

works as expected.