Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a snapshot of the master branch, built from commit e62f2239cd.
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value_from (2 of 2 overloads)

Convert an object of type T to value.

Synopsis

Defined in header <boost/json/value_from.hpp>

template<
    class T>
value
value_from(
    T&& t,
    storage_ptr sp = {});
Description

This function attempts to convert an object of type T to value using

Out of the box the function supports types satisfying SequenceContainer, arrays, arithmetic types, bool, std::tuple, std::pair, std::variant, std::optional, std::monostate, and std::nullopt_t. Conversion of other types is done by calling an overload of tag_invoke found by argument-dependent lookup. Its signature should be similar to:

void tag_invoke( value_from_tag, value&, T );

A value constructed with the storage_ptr passed to value_from is passed as the second argument to ensure that the memory resource is correctly propagated.

Exception Safety

Strong guarantee.

Template Parameters

Type

Description

T

The type of the object to convert.

Return Value

t converted to value.

Parameters

Name

Description

t

The object to convert.

sp

A storage pointer referring to the memory resource to use for the returned value. The default argument for this parameter is {}.

See Also

value_from_tag, value_to, tag_invoke: A general pattern for supporting customisable functions

Convenience header <boost/json.hpp>


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