Create a disengaged optional object.
Declared in <bslstl_optional.h>
optional(
std::allocator_arg_t allocatorArg,
AllocType allocator,
bsl::nullopt_t nullopt);Use the specified allocator to supply memory.
| Name | Description |
|---|---|
| allocatorArg | tag selecting the allocator-extended constructor |
| allocator | allocator used to supply memory |
| nullopt | disengaged-optional tag; value is unused |