diff --git a/src/corelib/global/qcompilerdetection.h b/src/corelib/global/qcompilerdetection.h index 9b609f76d0857c8aeef5d0b26b12786cf3260c2d..548eebd3ad784d87a477790e886386c5110c1858 100644 --- a/src/corelib/global/qcompilerdetection.h +++ b/src/corelib/global/qcompilerdetection.h @@ -618,7 +618,6 @@ # endif # if (__GNUC__ * 100 + __GNUC_MINOR__) >= 404 /* C++11 features supported in GCC 4.4: */ -# define Q_COMPILER_ATOMICS # define Q_COMPILER_AUTO_FUNCTION # define Q_COMPILER_AUTO_TYPE # define Q_COMPILER_CLASS_ENUM @@ -642,6 +641,11 @@ # define Q_COMPILER_RANGE_FOR # endif # if (__GNUC__ * 100 + __GNUC_MINOR__) >= 407 + /* GCC 4.4 implemented <atomic> and std::atomic using its old intrinsics. + * However, the implementation is incomplete for most platforms until GCC 4.7: + * instead, std::atomic would use an external lock. Since we need an std::atomic + * that is behavior-compatible with QBasicAtomic, we only enable it here */ +# define Q_COMPILER_ATOMICS /* GCC 4.6.x has problems dealing with noexcept expressions, * so turn the feature on for 4.7 and above, only */ # define Q_COMPILER_NOEXCEPT