I had intended to support the P2510R3 proposal unconditionally in C++20
mode, but I left it half implemented. The parse function supported the
new extensions, but the format function didn't.
This adds the missing pieces, and makes it only enabled for C++26 and
non-strict modes.
libstdc++-v3/ChangeLog:
PR libstdc++/110149
* include/std/format (formatter<const void*, charT>::parse):
Only alow 0 and P for C++26 and non-strict modes.
(formatter<const void*, charT>::format): Use toupper for P
type, and insert zero-fill characters for 0 option.
* testsuite/std/format/functions/format.cc: Check pointer
formatting. Only check P2510R3 extensions conditionally.
* testsuite/std/format/parse_ctx.cc: Only check P2510R3
extensions conditionally.
(cherry picked from commit 628ba410b9265dbd4278c1f1b1fadf05348adef2)
Jonathan Wakely
ae7cdc8c0f