As noted in PR 66146 comment 35, there is a new warning in the new
std::call_once implementation.
libstdc++-v3/ChangeLog:
* src/c++11/mutex.cc (std::once_flag::_M_finish): Add
maybe_unused attribute to variable used in assertion.
Tested powerpc64le-linux. Committed to trunk.
commit 9f9dbc8e09cf48406aa24b6c78735f1a7912cc4e
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Dec 17 13:16:02 2020
libstdc++: Fix -Wunused warning
As noted in PR 66146 comment 35, there is a new warning in the new
std::call_once implementation.
libstdc++-v3/ChangeLog:
* src/c++11/mutex.cc (std::once_flag::_M_finish): Add
maybe_unused attribute to variable used in assertion.
diff --git a/libstdc++-v3/src/c++11/mutex.cc b/libstdc++-v3/src/c++11/mutex.cc
index 4d42bed8ecc..93a5eae391d 100644
--- a/libstdc++-v3/src/c++11/mutex.cc
+++ b/libstdc++-v3/src/c++11/mutex.cc
@@ -74,7 +74,8 @@ std::once_flag::_M_finish(bool returning) noexcept
}
else
{
- int prev = __atomic_exchange_n(&_M_once, newval, __ATOMIC_RELEASE);
+ int prev [[maybe_unused]]
+ = __atomic_exchange_n(&_M_once, newval, __ATOMIC_RELEASE);
__glibcxx_assert(prev & _Bits::_Active);
// Wake any other threads waiting for this execution to finish.
constexpr int futex_wake = 129; // FUTEX_WAKE_PRIVATE
