Create and upstream a C23 %b printf directive patch

[skeeto]

Specifically a patch to add case 'b': to __pformat (print) and __mingw_sformat (scan):

https://github.com/mingw-w64/mingw-w64/blob/v13.0.0/mingw-w64-crt/stdio/mingw_pformat.c#L2346
https://github.com/mingw-w64/mingw-w64/blob/v13.0.0/mingw-w64-crt/stdio/mingw_sformat.c#L293

[Peter0x44]

Nearly done with this. Should be able to send it upstream shortly.
While I was working on it, I noticed there's a few "experimental" options w64devkit doesn't enable.

  --enable-experimental   Enable experimental features, valid options are
                          comma separated combination of all, dfp, printf128,
                          registeredprintf, softmath.

[skeeto]

Wow, great! Seems like you're enjoying contributing to uptream Mingw-w64?

I noticed there's a few "experimental" options w64devkit doesn't enable.

Interesting, I didn't know about this, thanks. I'll have to try it out. I can sort of guess what these things are about, and searching the mailing lists brings up some hints. Though I can't find anything on registeredprintf, and it doesn't appear to be used.

[Peter0x44]

Seems like you're enjoying contributing to uptream Mingw-w64?

Eh, maybe, more I'm just bored. These aren't particularly difficult things to implement, it's only a few hours of work.
I suppose it's nice "CV padding" as well.

I don't have ideas for any other patches to send, unless you do.

[Peter0x44]

Peter0x44/mingw-w64@75d0c95

[Peter0x44]

strtol also needs patches to parse 0bXXXX

[skeeto]

Nice! Thanks for doing this! I see it was merged about a day later. I put a couple of thoughts on the commit you shared, but I realize it's mostly just a copy-paste of __bigint_to_stringo (including various stylistic things I don't like, but when in Rome...), also to which those comments apply equally.

strtol also needs patches to parse 0bXXXX

Ah, I had no idea this was a new feature! I see in the standard:

If the value of base is 2, the characters 0b or 0B may optionally precede the sequence of letters and digits, following the sign if present.

strtoX already does too much (and, in one important way, not enough!), and now it's beyond too much. If you're relying on it to parse inputs, your program's behavior depends on which libc it happens to be linked against unless you take care to do additional parsing to restrict the input. But regardless of my feelings it's required for conformance!

This one I'll probably just wait for it to trickle down from upstream instead of extracting a patch. If you think this fulfills the issue, I'll let you close it.

[Peter0x44]

Well you opened it, I can't close it!

Anyway, I might have more patches to send later, should I cc you on those to get them reviewed by you too?

[Peter0x44]

I submitted a later commit with bug fixes too. Please also extract that one.
mingw-w64/mingw-w64@feb336b

[Peter0x44]

This commit fixes %o of 0 printing nothing for int128.

Technically w64devkit doesn't enable this so users can't use it. Though no one has requested it anyway. and I don't personally care either way.

[skeeto]

should I cc you on those to get them reviewed by you too?

If you'd like my review, sure! It seems Mingw-w64 moves quite quickly on accepting patches, so I'll try to review in a more timely manner.