On Mon, 13 Oct 2025 at 17:16, Tomasz Kaminski <[email protected]> wrote: > > > > On Mon, Oct 13, 2025 at 5:09 PM Patrick Palka <[email protected]> wrote: >> >> Series tested on x86_64-pc-linux-gnu, does this look OK for trunk only? >> >> -- >8 -- >> >> This FTM is like __cpp_explicit_this_parameter but is also defined >> in earlier C++ modes if deducing this is supported as an extension >> by the compiler. Currently only GCC supports this, Clang doesn't. >> >> libstdc++-v3/ChangeLog: >> >> * include/bits/c++config (_GLIBCXX_EXPLICIT_THIS_PARAMETER): >> New. >> --- > > As discussed, adjust the macro definition later, so this LGTM outside one > comment. > > >> >> libstdc++-v3/include/bits/c++config | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/libstdc++-v3/include/bits/c++config >> b/libstdc++-v3/include/bits/c++config >> index eec3a4a499dd..e6d8f186d0d4 100644 >> --- a/libstdc++-v3/include/bits/c++config >> +++ b/libstdc++-v3/include/bits/c++config >> @@ -927,6 +927,13 @@ namespace __gnu_cxx >> # define _GLIBCXX_USE_BUILTIN_TRAIT(BT) 0 >> #endif >> >> +// Whether deducing this is usable either officially, if in C++23 mode, or >> +// as an extension (Clang doesn't support the latter). >> +#if __cpp_explicit_this_parameter \ >> + || (__cplusplus >= 201103L && __GNUC__ >= 14 && !defined(_GLIBCXX_CLANG)) > > We always target only the version of GCC that we are compiled with, as far as > I understand, > so we could just make this #if __cpp_explicit_this_parameter && > !defined(_GLIBCXX_CLANG)?
I was wondering if it's relevant for Intel icx with the -fgnu-version option, but we defined _GLIBCXX_CLANG for icx, so it should be excluded by the _GLIBCXX_CLANG option. I don't think we need to support the EDG-based Intel icc on trunk now, so I agree that the __GNUC__ check seems redundant here. >> >> +# define _GLIBCXX_EXPLICIT_THIS_PARAMETER 202110L >> +#endif >> + >> // Mark code that should be ignored by the compiler, but seen by Doxygen. >> #define _GLIBCXX_DOXYGEN_ONLY(X) >> >> -- >> 2.51.0.491.g4b71b29477 >>
