Remove custom (v)snprintf as it's always available since C99

[Girgias]

I suppose we maybe could also get rid of our custom format conversion implementation format_converter() in snprintf.c (which would give us support for a and A modifier) by relying on the system one.

[nikic]

Ugh ... can we do something against this?

[Girgias]

Maybe change the format precision?

Also this is only a problem on ZTS RELEASE builds and Derick has no idea why the compiler is complaining.

[nikic]

I'm not sure about this. The custom snprintf definitely supports some non-standard things (like %H), though possibly those are not used for snprintf in particular.

[Girgias]

I'm not sure about this. The custom snprintf definitely supports some non-standard things (like %H), though possibly those are not used for snprintf in particular.

I'm gonna have a look through the code base with grep to see if some of the non standard formats are used and if yes how often.

Some of them, like v, can be changed to a standard one without any other changes.

I suppose some of the custom ones are for locale aware conversion?

[Girgias]

So I ran a grep regex (v)?(a)?s(n|l)?printf\(.*%(h|H|k|v|t|j|z|Z|l|L|I).*\) to see how many functions use custom formats and I get surprisingly few results [1].

I suppose we could move everything to use standard formats and use (v)snprintf even in the other custom functions so that we get rid of our custom format converter.

[1] https://gist.github.com/Girgias/b9a2b9926190630d433c84da0ef1b002

[Girgias]

Improved the regex to (v)?(a)?s(n|l)?printf\(.*%(\+|-| |#|0)?(\d+|\*)?(\.(\d+|\*))?(h|H|k|v|t|j|z|Z|l|L|I).*\) to cover prevision and length flags; and caught 5 more case. I've updated the gist https://gist.github.com/Girgias/b9a2b9926190630d433c84da0ef1b002/revisions

[ramsey]

@Girgias, please rebase to resolve the conflicts.

What's the status of this PR? Can we get it ready for 8.2?

[Girgias]

@Girgias, please rebase to resolve the conflicts.

What's the status of this PR? Can we get it ready for 8.2?

I'm not sure if extensions in the wild use snprintf() with our custom modifiers, I'll need to revisit this (if ever) later.