diff options
Diffstat (limited to 'development')
| -rw-r--r-- | development/c++.html | 6 | ||||
| -rw-r--r-- | development/c++/fwd-perfect.cc | 6 |
2 files changed, 10 insertions, 2 deletions
diff --git a/development/c++.html b/development/c++.html index 6b4fb47..94cc7fd 100644 --- a/development/c++.html +++ b/development/c++.html @@ -748,7 +748,11 @@ struct option { constexpr T& value() { assert(m_has_val); - return *reinterpret_cast<T*>(m_val); + // Placement new starts a new lifetime, launder pointer returned to the + // aligned storage. + // + // [1] https://en.cppreference.com/w/cpp/utility/launder + return *__builtin_launder(reinterpret_cast<T*>(m_val)); } private: diff --git a/development/c++/fwd-perfect.cc b/development/c++/fwd-perfect.cc index 2fafc3e..15bf2b4 100644 --- a/development/c++/fwd-perfect.cc +++ b/development/c++/fwd-perfect.cc @@ -54,7 +54,11 @@ struct option { constexpr T& value() { assert(m_has_val); - return *reinterpret_cast<T*>(m_val); + // Placement new starts a new lifetime, launder pointer returned to the + // aligned storage. + // + // [1] https://en.cppreference.com/w/cpp/utility/launder + return *__builtin_launder(reinterpret_cast<T*>(m_val)); } private: |