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boostorg / iostreams

Boost.org iostreams module
http://boost.org/libs/iostreams
Boost Software License 1.0
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Fix clang -Wtautological-type-limit-compare warnings. #155

Open Romain-Geissler-1A opened 1 year ago

Romain-Geissler-1A commented 1 year ago 
In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/filtering_streambuf.hpp:17: In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/chain.hpp:28: In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/detail/push.hpp:24: In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/detail/resolve.hpp:19: In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/detail/adapter/mode_adapter.hpp:24: In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/operations.hpp:16: In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/close.hpp:19: In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/detail/adapter/non_blocking_adapter.hpp:13: /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/seek.hpp:86:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') > 9223372036854775807 is always
 false [-Werror,-Wtautological-type-limit-compare]
               off > integer_traits<std::streamoff>::const_max ) )
               ~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/seek.hpp:85:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') < -9223372036854775808 is always false [-Werror,-Wtautological-type-limit-compare]
             ( off < integer_traits<std::streamoff>::const_min ||
               ~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/seek.hpp:113:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') > 9223372036854775807 is always false [-Werror,-Wtautological-type-limit-compare]
               off > integer_traits<std::streamoff>::const_max ) )
               ~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/mwrep/res/osp/Boost/23-0-0-0/include/boost/iostreams/seek.hpp:112:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') < -9223372036854775808 is always false [-Werror,-Wtautological-type-limit-compare]
             ( off < integer_traits<std::streamoff>::const_min ||
               ~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 errors generated.

Note: I am not sure this check on the offset is valid in the first place, I don't know how possible it is that stream_offset is a different type than std::streamoff in which case this check is totally pointless as always false.

pdimov commented 1 year ago

stream_offset is defined as boost::intmax_t here: https://github.com/boostorg/iostreams/blob/4d2e763ba8b88f3350fbea29b54507a3f5adf0f0/include/boost/iostreams/positioning.hpp#L36

mclow commented 1 year ago

std::streamoff is implementation defined; usually long long. See Cpp Reference

What platform (compiler, standard library) are you using?

Romain-Geissler-1A commented 1 year ago

This happened with clang 15 (so a release version) which was using glibc headers (the future 2.37 release, I think when I posted this pull request I used a snapshot of the master branch as of mid december) and libstdc++ headers (the future gcc 13 release, also a snapshot as of mid december).