https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107562
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:b457b779427b0f7b3fbac447811c9c52db5bc79e commit r13-3763-gb457b779427b0f7b3fbac447811c9c52db5bc79e Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Nov 8 00:35:09 2022 +0100 libstdc++: Fix up libstdc++ build against glibc 2.25 or older [PR107562] On Mon, Nov 07, 2022 at 05:48:42PM +0000, Jonathan Wakely wrote: > On Mon, 7 Nov 2022 at 16:11, Joseph Myers <jos...@codesourcery.com> wrote: > > > > On Wed, 2 Nov 2022, Jakub Jelinek via Gcc-patches wrote: > > > > > APIs. So that one can build gcc against older glibc and then compile > > > user programs on newer glibc, the patch uses weak references unless > > > gcc is compiled against glibc 2.26+. strfromf128 unfortunately can't > > > > This support for older glibc doesn't actually seem to be working, on an > > older system with glibc 2.19 I'm seeing > > > > /scratch/jmyers/fsf/gcc-mainline/libstdc++-v3/src/c++17/floating_to_chars.cc:52:3: error: expected initializer before '__asm' > > 52 | __asm ("strfromf128"); > > | ^~~~~ > > > > and a series of subsequent errors. > > This seems to "fix" it (not sure if it's right though): > > #ifndef _GLIBCXX_HAVE_FLOAT128_MATH > extern "C" _Float128 __strtof128(const char*, char**) > __attribute__((__weak__)); > #endif > extern "C" _Float128 __strtof128(const char*, char**) > __asm ("strtof128"); It is, but floating_from_chars.cc has the same problem, and I think we can avoid the duplication, like this: 2022-11-08 Jakub Jelinek <ja...@redhat.com> PR libstdc++/107562 * src/c++17/floating_from_chars.cc (__strtof128): Put __asm before __attribute__. * src/c++17/floating_to_chars.cc (__strfromf128): Likewise.
