Re: gnulib and *printf

[Bruno Haible]

Hi Joel,

> I use snprintf like this:
> 
>   field_width = snprintf (NULL, 0, " %d", max_value);
> 
> Later I use field_width for a "%*d" conversion on all rows of the table.  
> I don't have much experience with mbswidth, but I don't think it can be 
> useful here.

Indeed, in your case it is de facto guaranteed that all table cells will be
ASCII strings, so that strlen and mbswidth return the same value.

> > This does not look very reusable: 80% of the programs don't use obstacks, 
> > 95%
> > of the programs don't use 'dprintf', and 30% of the programs are LGPL and
> > cannot use 'xvasprintf'.
> 
> Forgetting licensing issues for a moment, what harm is there in including 
> a module you don't currently need?  My guess was that the harm is none or 
> just some minor size increase.  Is it worse than that?

A certain number of gnulib users want to get the functionality they need,
and not more. If gnulib copies into their module code that they deem not
necessary - and for which we cannot explain the necessity - they start
using words like "bloat" or "creeping dependencies".

The harm that a module with too many dependencies does is that it does not
increase gnulib's reputation with people who think this.

> To find the full list of printf modules, I just used 
> "ls modules/*printf*".

OK, that was easy enough. I guess most people do the same.

> But I figured a project's list of modules would be  
> easier to check if it listed only 1 module in place of potentially 15 
> *printf-posix modules.  Moreover, if ever gnulib grows a new printf module 
> that a project needs (is there anything for wprintf yet?), the project's 
> maintainers wouldn't have to remember to add it.

But if the project does not use the function? For example, the latest addition
to the list of *printf functions was 'dprintf'. gnulib added support for this.
But if your project does not use dprintf(), then you don't have to add it.
Therefore tracking the list of all *printf functions is normally not useful.

> Of course, Eric has shown me -DGNULIB_POSIXCHECK.  I haven't explored it 
> extensively yet, but it seems to improve the situation.

Yes, -DGNULIB_POSIXCHECK is a step towards finding the modules that your
project needs.

Bruno