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Detecting Parameter in Function-Call ...

Hi Experts,

I'm writing a function which has to write a given Message to :
  1) a Rx-RichEdit (given parameter)
and/or
  2) a LogFile on disk (given parameter)

Here's my function definition :
Function  WriteMessage(rxreLog: TRxRichEdit ; Msg: String ; strLogFile: String ;
                       colKleur: TColor) : Boolean;


This is what I want to do :
If the user passes NIL for rxreLog, then the message should not be written to the rxRichEdit.

If the user passes '' for strLogFile, then the message should not be written to the logfile on disk.


Now my question :
How can I detect if the rxreLog-parameter is nil ?
The following statement doesn't work :
  if rxreLog = nil then
    DoNothing
  else
    DoWrite


Can someone please help me out with this ?


Thanx in advance.

The Mayor.
0
wimmeyvaert
Asked:
wimmeyvaert
1 Solution
 
craig_capelCommented:
have you tried... if rxrelog = 0 then
  do nothing?
0
 
TheNeilCommented:
I don't know about rxRichEdit but using standard RichEdit your test will always return FALSE (i.e. rxreLog is NOT nil) unless you specifically set rxreLog to nil (e.g. rxreLog := nil)

You might be better off passing something other than a RichEdit (or variation) OR passing another value holding something like the line count (-1 indicating no lines). No better ideas I'm afraid

The Neil
0
 
markshifferCommented:
if rxeLog = nil then
....

rxeLog is just a pointer so you can test directly for nil

what error do you get?
0
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kretzschmarCommented:
? what about
if assigned(rxelog) then
  //doall
else
  //donothing
0
 
jhook010598Commented:
if not assigned(rxelog) then
  //donothing
else
  //dosomething
end
0
 
rwilson032697Commented:
Can you show us how you are calling the function?
0
 
kretzschmarCommented:
to jhook,
i don't like negative conditions,
therefore i've changed the order in my comment ;-)
0
 
StefaanCommented:
Yo Mayor,

Zeg manneke da mocht ge altijd aan mij persoonlijk vragen ook zunne ;-)

E-mail : Stefaan.Lesage@dexia.be
0
 
MadshiCommented:
"if Assigned(object) then" is exactly the same as "if object = nil then". Both should work alright. Where is the problem? It works for me!   :-)

Regards, Madshi.
0
 
wimmeyvaertAuthor Commented:
Hi,

I want to thank everybody for the fast replies.

My conclusion is that the comment of Kretzschmar is the best solution for me.
So I grant the points to you ;-)


Greetings,
The Mayor

P.S. : Is there a possibility to split the points and give them to 2 experts?
If so, how can you do this?
0
 
StefaanCommented:
Hi Mayor,

Well there isn't exacly a way to split the points.  Normally we simply post a new question for a specific person, so that he/she can get the points too ;-)

Best regards,


Stefaan

a.k.a. Kingetje

P.S. : I'll call you this or next week
0
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