reent.h

[Jeff Johnston]

Artem B. Bityuckiy wrote:
> Jeff Johnston wrote:
> 
>>> 1. Does Newlib really take care about binary compatibility?
>>
>> In this particular case, care was taken to see that the entire library 
>> didn't require recompiling everytime a new reentrancy field was 
>> added.  Newlib hasn't got proper dependency statements in its make 
>> files so moving all the reentrancy fields around requires almost a 
>> complete rebuild; the makefiles do not catch this.  At the time, the 
>> old malloc area was still in place but not being used so the first 
>> change started to reclaim the area with the union.
>>
>>> 2. I want to add new fields to struct _reent. Do I need to add these 
>>> fields to _reent field of _new union to support binary compatibility? 
>>> May I not to care about binary compatibility and have no problems 
>>> during future contributions to Newlib?
>>
>>
>>
>> Add them there in the non-reent-small case for the reason explained 
>> above.
>>
>>> 3. In case of REENT_SMALL defined there is no reserved space in 
>>> struct _reent. Should I use struct misc_reent * ?
>>>
>>
>> Yes, unless the new variables naturally belong with some of the other 
>> groupings.  Remember to change the initialization code too.
> 
> Yes, I did this.
> 
>>
>> -- Jeff J.
>>
> Ok, I've added my field to struct _misc.
> 
> We've implemented setlocale() and this field is _locale_t structure. But 
> there is old locale-related field (_current_locale) present. It isn't 
> needed anymore. We can't delete it without struct _reent size affecting. 
> Should we just leave this field alone?
> 

Yes, do not remove it for the reason you quoted.  Add a comment that the field 
is no longer used and can be reclaimed when space is needed.  You can even try 
renaming it (e.g. __no_longer_used) to verify that there aren't any references 
you have missed.

-- Jeff J.