On 2012-01-25 11:36-0000 Andrew Ross wrote:

> On Wed, Jan 25, 2012 at 11:06:06AM +0100, Arjen Markus wrote:
>> Hi Andrew,
>>
>> On 2012-01-25 10:57, Andrew Ross wrote:
>>
>>> If the string contained characters, then just the characters were passed
>>> (with trailing spaces removed). If a null string was passed (i.e. of
>>> length 0), then the returned string was a C NULL string. If the fortran
>>> string was of length > 0, but was all spaces, then a single space was
>>> passed to C. This seems entirely arbitrary. It made the examples work,
>>> but wouldn't definitely do what the user expected.
>>>
>>> I suggest we continue as we are following Alan's changes, i.e. pass
>>> EXACTLY the fortran string to C. The onus is then on the user to ensure
>>> the string is the right length or to strip any unnecessary spaces. We
>>> can't do this manually since we don't know which trailing spaces are
>>> necessary and which are not.
>>>
>>> This will be an API change for the f95 bindings, and will require
>>> a number of examples to be updated. Are people happy with this?
>>>
>>
>> Well, what I have been thinking about is the following:
>> Rather than divine (in the spirit of the old implementation) if trailing
>> blanks are significant, let the user append an achar(0) as the last
>> character if trailing blanks are significant. I will rework the
>> examples to incorporate that.
>>
>> It can be as simple as:
>>
>>       call pllab( 'Tight string     ', &
>>                   'String with trailing blanks     '//achar(0))
>>
>> We can even define a PL_END_OF_STRING parameter to the module, so that
>> this implementation detail is hidden.
>>
>> That way the changes are minimal - we will need to document this of course.
>
> I like this idea better as most of the time users won't want the trailing
> spaces.
>
> Would be less invasive changes to the examples as well.

Thanks to both of you for looking into this issue deeper than I did.
You appear to have reached consensus between you on the best thing
to do so I will be happy to go along with that.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
__________________________

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