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atomic<T*>
inheritance from atomic_address
breaks type safetySection: 33.5.8 [atomics.types.generic] Status: Resolved Submitter: BSI Opened: 2010-08-25 Last modified: 2016-01-28
Priority: Not Prioritized
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Discussion:
Addresses GB-133
The free functions that operate on atomic_address
can be
used to store a pointer to an unrelated type in an atomic<T*>
without a cast. e.g.
int i; atomic<int*> ai(&i); string s; atomic_store(&ai,&s);
Overload the atomic_store
, atomic_exchange
and
atomic_compare_exchange_[weak/strong]
operations for
atomic<T*>
to allow storing only pointers to T
.
[ 2010-10-27 Daniel adds: ]
Resolving this issue will also solve 1467(i)
Accepting n3164 would solve this issue by removingatomic_address
.
[Resolved in Batavia by accepting n3193. ]
Proposed resolution:
Add the following overloads to 33.5.8 [atomics.types.generic], the synopsis around the specialization
atomic<T*>
, as indicated:
namespace std { [..] template <class T> struct atomic<T*> : atomic_address { [..] }; template<typename T> void atomic_store(atomic<T*>&,T*); template<typename T> void atomic_store(atomic<T*>&,void*) = delete; template<typename T> void atomic_store_explicit(atomic<T*>&,T*,memory_order); template<typename T> void atomic_store_explicit(atomic<T*>&,void*,memory_order) = delete; template<typename T> T* atomic_exchange(atomic<T*>&,T*); template<typename T> T* atomic_exchange(atomic<T*>&,void*) = delete; template<typename T> T* atomic_exchange_explicit(atomic<T*>&,T*,memory_order); template<typename T> T* atomic_exchange_explicit(atomic<T*>&,void*,memory_order) = delete; template<typename T> T* atomic_compare_exchange_weak(atomic<T*>&,T**,T*); template<typename T> T* atomic_compare_exchange_weak(atomic<T*>&,void**,void*) = delete; template<typename T> T* atomic_compare_exchange_weak_explicit(atomic<T*>&,T**,T*,memory_order); template<typename T> T* atomic_compare_exchange_weak_explicit(atomic<T*>&,void**,void*,memory_order) = delete; template<typename T> T* atomic_compare_exchange_strong(atomic<T*>&,T**,T*); template<typename T> T* atomic_compare_exchange_strong(atomic<T*>&,void**,void*) = delete; template<typename T> T* atomic_compare_exchange_strong_explicit(atomic<T*>&,T**,T*,memory_order); template<typename T> T* atomic_compare_exchange_strong_explicit(atomic<T*>&,void**,void*,memory_order) = delete; }