Locale vs. Number formatting

[John Darrington]

Ever since I've been hacking on pspp, we've been using printf et al for 
data-in/out functions.   When we introduced i18n, this caused a problem, 
because printf is dependent upon the LC_NUMERIC locale category.

We avoided this problem, simply by setting all categories *except* LC_NUMERIC
This seems to have worked until now (bug #37366).  I cannot reproduce the 
problem - but I suspect it has to do with the later version of libc that
Mindaugus is using.  From the trials that Mindaugus has been doing I suspect,
that the problem pertains to the thread safety (or lack thereof) with the 
setlocale
function.  It seems the black magic we've been using to set all locale 
categories
except LC_NUMERIC is working only in certain threads.

If I am right that this is a libc is the independent variable, then we can 
expect
a lot of users to start complaining after their operating systems get upgraded.
Mindaugus correctly points out that ignoring the LC_NUMERIC locale is not good 
anyway (it means that certain aspects of the GUI don't get displayed as users 
might want).  So I think we need to fix the problem, not just the symptom.  
That 
is to say, we should set ALL locale categories, and deal with the consequences 
where, in the past we have relied upon the C locale behaviour.

There are several approaches that I can think of:

1. Use write a set of c-printf functions. Unfortunately, there aren't any in 
gnulib.

2. Surround all the relavate *printf calls with setlocale calls to set the 
locale to
   C and back again afterwards.

3. I think the only locale pertinent thing is the decimal separator.  
Furthermore, I 
   think I am correct, when I say that all locales use either '.' or ',' So we 
could
   deal with the printed strings dealing with an occurence of either as a 
decimal 
   separator.

4. Can we start using the newlocale function ?

Other suggestions?

J'







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