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| author | Johannes Stoelp <johannes.stoelp@gmail.com> | 2023-08-01 23:36:27 +0200 |
|---|---|---|
| committer | Johannes Stoelp <johannes.stoelp@gmail.com> | 2023-08-01 23:36:27 +0200 |
| commit | e6cab7826a010b34670e825650167b0d975d5819 (patch) | |
| tree | 45ea0a085da64d6255a4011a781ba481e5e6161c | |
| parent | 5778d4cb2db3081aa346f66cf3f3b7500b342dc6 (diff) | |
| download | notes-e6cab7826a010b34670e825650167b0d975d5819.tar.gz notes-e6cab7826a010b34670e825650167b0d975d5819.zip | |
c++: fix option example by laundering returned ptr
| -rw-r--r-- | src/development/c++/fwd-perfect.cc | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/development/c++/fwd-perfect.cc b/src/development/c++/fwd-perfect.cc index 2fafc3e..15bf2b4 100644 --- a/src/development/c++/fwd-perfect.cc +++ b/src/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: |