Christian S.
15th January 2005 19:06 UTC

FileOpen in a not permitted directory
Hello!

I tried to use the following script to determine, wether the user has the permission to write into the installation directory or not.

Function OnDirLeave
  ClearErrors
  SetOutPath $INSTDIR
  
  FileOpen $0 "test.dat" "w"
  ;StrCmp $0 "" notPossible possible
  IfErrors notPossible possible
  

notPossible:
  MessageBox MB_OK "Not able to write into this directory!"
  Abort
possible:
  FileClose $0
FunctionEnd

According to the helpfile and what I'm used to when working with files under windows, it should have worked, what means, that FileOpen should not have worked.

But it did! Checking the permissions with this function failed!

So I tried the following one, which solved the problem:

Function OnDirLeave
  ClearErrors
  SetOutPath $INSTDIR
  
  FileOpen $0 "test.dat" "w"
  FileWriteByte $0 "0"
  IfErrors notPossible possible
  
notPossible:
  MessageBox MB_OK "Not able to write into this directory!"
  Abort
possible:
  FileClose $0
  Delete "$INSTDIR\test.dat"
FunctionEnd

Now my question is, if anyone can explain to me, why the first version didn't work!

TIA
Christian

P.S.: Please excuse my poor english!