__is_trivial

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Category

Type Trait Functions

Syntax

bool __is_trivial( typename T )

Returns true if and only if T is a trivial type.

Error if T is an incomplete type.

Trivial types are defined in Section 3.9 p10 of the Working Draft.

Trivial classes are defined in Section 9 p5 of the Working Draft.

Returns true if T is both const and volatile qualified.

A type is trivial if it is:

  • a scalar type
  • an array of trivial types
  • a class/union type where all 4 special members are trivial:
    • default constructor
    • copy constructor
    • copy assignment operator
    • destructor

Consult this online help for the definition of each __has_trivial_* traits.

Trivial types trigger several special clauses in the standard, which may affect code generation and optimizations, or simply whether certain constructs are undefined.

Note that trivial types are a generalization of PODs (plain old data objects) in the 2003 standard, if the POD/trivial refinement has not happened when this type function is initially implanted.

See Also