QAtomic: introduce loadRelaxed() / storeRelaxed()

Plain load() / store() have already relaxed semantics. This
can be surprising -- std::atomic::load()/store() are actually
sequentially consistent -- and introduce a pain point
if someone wants to move from Qt atomics to std:: atomics.

So just add a suffix to the functions to clarify what's the
memory ordering involved with them.

The Ops::load / ::store are temporarily left in, because other
modules depends on them. We need to port those modules away,
then they can go (it's private API anyhow).

Similarly, not deprecating anything yet, except for marking
obsolete in the docs; there's a lot of code around using
load() / store() that needs to be ported first.

[ChangeLog][QtCore][QAtomicInteger] Added loadRelaxed() and
storeRelaxed(), to be used as replacements of load() / store().

[ChangeLog][QtCore][QAtomicPointer] Added loadRelaxed() and
storeRelaxed(), to be used as replacements of load() / store().

Change-Id: Iab0a78885050379e3740f0b039ba2bef28ce3bd2
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

1 files changed, 3 insertions, 1 deletions

diff --git a/src/corelib/thread/qatomic.h b/src/corelib/thread/qatomic.h
index 280ce96b76..7990db2fd9 100644
--- a/src/corelib/thread/qatomic.h
+++ b/src/corelib/thread/qatomic.h
@@ -81,8 +81,10 @@ public:
 
 #ifdef Q_CLANG_QDOC
     T load() const;
+    T loadRelaxed() const;
     T loadAcquire() const;
     void store(T newValue);
+    void storeRelaxed(T newValue);
     void storeRelease(T newValue);
 
     operator T() const;
@@ -172,7 +174,7 @@ public:
 #else
     inline QAtomicPointer(T *value = nullptr) noexcept
     {
-        this->store(value);
+        this->storeRelaxed(value);
     }
 #endif
     inline QAtomicPointer(const QAtomicPointer<T> &other) noexcept