On Wed, Dec 17, 2025 at 1:41 PM Jonathan Wakely <[email protected]> wrote:
> On Wed, 17 Dec 2025 at 12:38, Jonathan Wakely <[email protected]> wrote: > > > > On Wed, 17 Dec 2025 at 10:34, Tomasz Kamiński <[email protected]> > wrote: > > > > > > Defining the new implementation inside the _V2 inline namespace, > > > would guaranteed TUs using old definition (GCC-15 or ones defining > > > _GLIBCXX_USE_OLD_GENERATE_CANONICAL) will observe old behavior > > > (call old implementation) when linked against TUs using new > > > implementation. > > > > > > This updates random/pr60037-neg.cc to accept static assertion > > > with a given message on any line number. Preventing need for > > > constant updates. > > > > > > libstdc++-v3/ChangeLog: > > > > > > * include/bits/random.h (generate_canonical) > > > [!_GLIBCXX_USE_OLD_GENERATE_CANONICAL]: Define inside > > > _V2 inline namespace. > > > * include/bits/random.tcc (generate_canonical) > > > [!_GLIBCXX_USE_OLD_GENERATE_CANONICAL]: Likewise. > > > * testsuite/26_numerics/random/pr60037-neg.cc: Make > > > test independed on line of which static assert is placed. > > > > "independent of line on which" > > FWIW, I used this commit msg in my local commit. The extra text about > the change to the test might be worth using ... but on the other hand > it's a lot of words for a tiny change to one test! > > libstdc++: Move new std::generate_canonical to inline namespace > > This ensures that the new definition of std::generate_canonical has a > different mangled name from the old one, so that TUs compiled with GCC > 16 will be sure to use the new definition, even if the linker also sees > a symbol instantiated from the old definition. We use the same _V2 > inline namespace as used elsewhere (std::_V2::condition_variable, > std::_V2::__rotate, and std::chrono::_V2::system_clock), and use a macro > to add it conditionally so that it's not used for the ABI-unstable > gnu-versioned-namespace configuration. > This is much nicer description, and will be useful for someone who will wonder why _V2 was used, so I would suggest that you post your local change. > > We can simplify the 26_numerics/random/pr60037-neg.cc test to only use > one dg-error without a line number, so that it matches any of the three > relevant static_assert failures for this test: the one from _Adaptor in > <bits/random.h> and the ones from the new and old definitions of > std::generate_canonical in <bits/random.tcc>. Without this change, the > line number for the dg-error matching the <bits/random.tcc> error epends > on the _GLIBCXX_USE_OLD_GENERATE_CANONICAL macro, which is awkward to > depend on in the test (because DejaGnu sees all dg-error directives, it > doesn't care if they're guarded by #ifdef preprocessor checks). > > libstdc++-v3/ChangeLog: > > * include/bits/random.h [!_GLIBCXX_USE_OLD_GENERATE_CANONICAL] > (generate_canonical): Use inline namespace _V2. > * include/bits/random.tcc [!_GLIBCXX_USE_OLD_GENERATE_CANONICAL] > (generate_canonical): Likewise. > * testsuite/26_numerics/random/pr60037-neg.cc: Remove lineno so > that one dg-error matches both diagnostics. > >
