delphi TFileStream.create

Value	Meaning
fmCreate	Create a file with the given name. If a file with the given name exists, open the file in write mode.
fmOpenRead	Open the file for reading only.
fmOpenWrite	Open the file for writing only. Writing to the file completely replaces the current contents.
fmOpenReadWrite	Open the file to modify the current contents rather than replace them.
fmShareCompat	Sharing is compatible with the way FCBs are opened.
fmShareExclusive	Other applications can not open the file for any reason.
fmShareDenyWrite	Other applications can open the file for reading but not for writing.
fmShareDenyRead	Other applications can open the file for writing but not for reading.
fmShareDenyNone	No attempt is made to prevent other applications from reading from or writing to the file.

The share mode must be one of the following values:

Value	Meaning
fmShareCompat	Sharing is compatible with the way FCBs are opened.
fmShareExclusive	Other applications can not open the file for any reason.
fmShareDenyWrite	Other applications can open the file for reading but not for writing.
fmShareDenyRead	Other applications can open the file for writing but not for reading.
fmShareDenyNone	No attempt is made to prevent other applications from reading from or writing to the file.