tree 315a37f90ee2839f21ee0ef91e5159d5ff7cbd75
parent a4ac099487d057dde8151700b3802eaeb69cead2
author Mark de Wever <koraq@xs4all.nl> 1707581393 +0100
committer GitHub <noreply@github.com> 1707581393 +0100
gpgsig -----BEGIN PGP SIGNATURE-----
 
 wsFcBAABCAAQBQJlx5/RCRC1aQ7uu5UhlAAAnOUQAKW72UccxLa3dYzp/Cy7/I5c
 UPgsfOQZHgpw1QDIgCaCQ+mqpXLKW1J/pp4LkN48SVDl1QAHOzGd/mTnLDWZavjr
 JM3S+7fkR5hhGUl/Ed8eFwu+XRetMN6nFTe3QUgCEYRQn6bJ4hQmIjONsAFfTKut
 xiKMcnt2t1slHcFcE1ulOQaKTSQA3a1RPSmOezgdOhGyj2mJeROSbSHiKzrilk/K
 FE7OFoOakn+rwuRQQkbGCl4rRFAeYEdAPSfY3mVCLHAIFFrlscgs57GAEEcciAyp
 16B3prR6u5L746w5NPqd3lADygodpkiHKsQnytC8pbd+anJZbUVi+QPNF5ow9dpr
 KpNopHZEQKTK7K8M6byOMofSYHwWlAt1H3UP0XP8MMzdqzrVgjzqLmWrmYbm7U0p
 I8+kUlybY957x9YpUO8VF7x0nZjECDUa0ndI6T5YlSZ6omBiQ6oQNAIOczM3Qwlc
 ATD9vShddwStoXnd/JdMDuW0uY9HPVO6Wu3JBA3tvqNYJLd9Q0VB1M+eSNrv9qB0
 i7IyseVAItFRPaMC16z5GvYsl0a8H/0ZQrS+CuYw2Lkv7+hPuoT7N6m3tuHBqIsV
 +kH1h8kfGUf12/g1iJIVJr9JNYEUTzYzfo4GmZ1PjJREBY1vAlofMUihsbCMRBLO
 U7TZqgyyf+dRKx3Df6i/
 =66hR
 -----END PGP SIGNATURE-----
 

[libc++][print] Moves is_terminal to the dylib. (#80464)

Having the test in the header requires including unistd.h on POSIX
platforms. This header has other declarations which may conflict with
code that uses named declarations provided by this header. For example
code using "int pipe;" would conflict with the function pipe in this
header.

Moving the code to the dylib means std::print would not be available on
Apple backdeployment targets. On POSIX platforms there is no transcoding
required so a not Standard conforming implementation is still a useful
and the observable differences are minimal. This behaviour has been done
for print before https://github.com/llvm/llvm-project/pull/76293.

Note questions have been raised in LWG4044 "Confusing requirements for
std::print on POSIX platforms", whether or not the isatty check on POSIX
platforms is required. When this LWG issue is resolved the
backdeployment targets could become Standard compliant.

This patch is intended to be backported to the LLVM-18 branch.

Fixes: https://github.com/llvm/llvm-project/issues/79782