| Re: keywords and passing values [message #54869] |
Mon, 16 July 2007 11:31  |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
|
Conor writes:
> I don't see why your example wouldn't work either. I can only assume,
> therefore, that you have a bug somewhere, possibly in your testing? I
> really don't know though, sorry...
I agree the example should work. Is this the *real* example?
Or, are you calling superclass GetProperty methods in
the real program? That could definitely result in pass-by-reference
problems and is the reason I *always* use _REF_EXTRA keywords
in GetProperty definitions.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
|
|
|
|
| Re: keywords and passing values [message #54870 is a reply to message #54869] |
Mon, 16 July 2007 11:00  |
Conor
Messages: 138
Registered: February 2007
|
Senior Member |
|
|
On Jul 16, 12:49 pm, Ingo von Borstel <newsgro...@planetmaker.de>
wrote:
> Hi there,
>
> I probably have - again - an issue with parameters and calling by
> reference and value. But I don't see where I miss something as the same
> works in other places:
>
> I have a set of routines (actually object routines) that take a
> parameter "valid". What I do is along these lines (added line numbers
> for reference):
>
> 1 myobj::setdata, var
> 2 valid = 1
> 3 objnum = self->getdata_index(var,valid=valid,_extra=extra)
> 4 IF NOT valid THEN PRINT, "creating new data!"
> 5 END
>
> 7 FUNCTION myobj::getdata_index, var, valid=valid, $ (some other keywords)
> 8 valid = 1
> 9 (check for several things and return the search result, if successful)
> 10 valid = 0
> 11 RETURN, -1
> 12 END
>
> If I now call the print routine with a variable value that will fail,
> print itself never gets reported that its subroutine, getdata_index
> returned valid=0, though I checked in line 11 that valid=0
>
> IDL> myobj->print, 'not existent'
> IDL>
>
> Funnily, if I trace the programme and stop in line 4, call
> IDL> valid = 1 & print, getdata_index(var,valid=valid) & print, valid
> -1 0
> IDL>
> I get the results I want (valid=0).
>
> I'm a bit puzzled right now and don't see where something is missing.
>
> Best regards & thanks for any advice,
> Ingo
> --
> Ingo von Borstel <newsgro...@planetmaker.de>
> Public Key:http://www.planetmaker.de/ingo.asc
>
> If you need an urgent reply, replace newsgroups by vgap.
Well, this works:
pro test,valid=valid
valid = 1
end
test,valid=valid
print,valid
; prints 1
I don't see why your example wouldn't work either. I can only assume,
therefore, that you have a bug somewhere, possibly in your testing? I
really don't know though, sorry...
|
|
|
|
| Re: keywords and passing values [message #54901 is a reply to message #54869] |
Thu, 19 July 2007 08:06 |
Ingo von Borstel
Messages: 54
Registered: September 2006
|
Member |
|
|
Hi,
>
>> I don't see why your example wouldn't work either. I can only assume,
>> therefore, that you have a bug somewhere, possibly in your testing? I
>> really don't know though, sorry...
>
> I agree the example should work. Is this the *real* example?
In principle yes, though I left out some pieces that contain if then
else, but do not manipulate any of the variables.
> Or, are you calling superclass GetProperty methods in
> the real program? That could definitely result in pass-by-reference
> problems and is the reason I *always* use _REF_EXTRA keywords
> in GetProperty definitions.
Indeed, the use of _ref_extra did the trick. I'm still not entirely sure
as of why, though. I'll did through my code and add it to all routines
of this object...
Best regards & thanks,
Ingo
--
Ingo von Borstel <newsgroups@planetmaker.de>
Public Key: http://www.planetmaker.de/ingo.asc
If you need an urgent reply, replace newsgroups by vgap.
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
