bsltf_movabletesttype

Detailed Description

Outline

• Purpose
• Classes
• Description
  • Attributes
  • Usage
    • Example 1: Printing the Supported Traits

Purpose

Provide a non-allocating test class that records when moved from.

Classes

• bsltf::MovableTestType: non-allocating test class that records moves

See also

bsltf_templatetestfacility

Description

This component provides a single, unconstrained, non-allocating (value-semantic) attribute class, MovableTestType, that records when the move constructor or assignment operator is called with the instance as the source argument. This class is not bitwise-moveable, and will assert on destruction if it has been copied (or moved) without calling a constructor. This class is primarily provided to facilitate testing of templates where move semantics need to be differentiated versus copy semantics.

Attributes

Name                Type             Default
------------------  ---------------  -------
data                int              0
movedInto           MoveState::Enum  e_NOT_MOVED
movedFrom           MoveState::Enum  e_NOT_MOVED

• data: representation of the object's value
• movedInto: indicates whether a move constructor or move assignment operator was used to set the value of this object.
• movedFrom: indicates whether a move constructor or move assignment operator was used to move out the value of this object.

Usage

This section illustrates intended use of this component.

Example 1: Printing the Supported Traits

Suppose we wanted to print the supported traits of this test type.

First, we create a function template printTypeTraits with a parameterized TYPE:

template <class TYPE>
void printTypeTraits()
    // Prints the traits of the parameterized 'TYPE' to the console.
{
    if (bslma::UsesBslmaAllocator<TYPE>::value) {
        printf("Type defines bslma::UsesBslmaAllocator.\n");
    }
    else {
        printf(
            "Type does not define bslma::UsesBslmaAllocator.\n");
    }
 
    if (bslmf::IsBitwiseMoveable<TYPE>::value) {
        printf("Type defines bslmf::IsBitwiseMoveable.\n");
    }
    else {
        printf("Type does not define bslmf::IsBitwiseMoveable.\n");
    }
}

Now, we invoke the printTypeTraits function template using MovableTestType as the parameterized TYPE:

printTypeTraits<MovableTestType>();

Finally, we observe the console output:

Type does not define bslma::UsesBslmaAllocator.
Type does not define bslmf::IsBitwiseMoveable.