[PATCH] misc: Add mkostempat (BZ 19866)

[Paul Eggert]

On 2026-06-22 09:35, Adhemerval Zanella Netto wrote:
> 
> 
> On 22/06/26 13:22, Paul Eggert wrote:
>> On 2026-06-22 06:57, Adhemerval Zanella Netto wrote:
>>> I am working a v2 based on this design, I am still not convinced on adding
>>> the callback-like interface to allow openat2.
>>
>> The case for the more-complicated interface would be stronger if we had actual use cases for it. We already have real use cases based on the callback-like approach in Gnulib. What are the real uses cases for the more-complicated interface, use cases that the callback-like approach can't do?
> 
> I am trying to focus on the original bug report issue, instead of trying
> to come up with a more complicated interface that required more setup and
> care to be used (and the callback still has the very versioning issues, as
> nftw/fts shows).

Sounds like we're in disagreement then, about how to address the 
original bug report. Let me summarize where I think the 
callback-oriented approach is better.

First, a callback-oriented API is simpler (fewer arguments and easier to 
explain) than the many-argument API. We can cut the callback API down to 
three arguments: char *template, the function, and void *function-arg.

Second, there aren't versioning issues in the callback-oriented API. 
nftw/fts's versioning issues don't apply here, because the callback 
function accepts only char * and void *: the char * is a mutable string 
and that won't change, and the void * is up to the application. There 
are no tricky types like off_t or time_t or struct stat.

Third. the callback-oriented approach is more general, and solves real 
problems (e.g., GNU 'cp' creating symlinks) that the more-complicated 
API does not address.

Fourth, although I concede that the callback approach does mean callers 
must define a callback function, that's a relatively minor drawback: 
glibc already has multiple APIs that already use callbacks, developers 
are already well-acquainted with the idea of callbacks, and these 
callback functions will be relatively simple.