template <class T> struct has_trivial_assign : public
If a type has a trivial assignment-operator then the operator has the same
effect as copying the bits of one object to the other: calls to the operator
can be safely replaced with a call to
Compiler Compatibility: If the compiler does not support partial-specialization of class templates, then this template can not be used with function types.
Without some (as yet unspecified) help from the compiler, has_trivial_assign
will never report that a user-defined class or struct has a trivial constructor;
this is always safe, if possibly sub-optimal. Currently (May 2011) compilers
more recent than Visual C++ 8, GCC-4.3, Greenhills 6.0, Intel-11.0, and Codegear
have the necessary compiler intrinsics
to ensure that this trait "just works". You may also test to see
if the necessary intrinsics
are available by checking to see if the macro
C++ Standard Reference: 12.8p11.
has_trivial_assign<char*>::typeis the type
has_trivial_assign<int (*)(long)>::valueis an integral constant expression that evaluates to true.
has_trivial_assign<MyClass>::valueis an integral constant expression that evaluates to false.
has_trivial_assign<T>::value_typeis the type