This struct is a component‐private meta‐function. Do not use. This meta‐function checks whether the template parameter type VISITOR has the member ResultType defined using "SFINAE" (Substitution Failure Is Not An Error). A value of true indicates VISITOR::ResultType exists, and false otherwise.
Synopsis
Declared in <bdlb_variant.h>
template<class VISITOR>
struct Variant_ReturnValueHelper
: bsl::integral_constant<bool, sizeof (Variant_ReturnValueHelper_Matcher::match<VISITOR>(0)) == sizeof(Variant_ReturnValueHelper_YesType)>Base Classes
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Description |
Metafunction representing a compile‐time constant of the specified (template parameter) |
Type Aliases
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Alias for this |
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Member Functions
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Description |
Return a copy of the template argument |
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