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std::basic_..._arg::handle(3)  C++ Standard Libary std::basic_..._arg::handle(3)

NAME
     std::basic_format_arg::handle - std::basic_format_arg::handle

Synopsis
	Defined in header <format>
	template< class Context >		  (since C++20)
	class basic_format_arg<Context>::handle;

	A type-erased wrapper that allows formatting an object of a user-defined
     type.

	handle	objects  are  typically created by std::make_format_args and ac-
     cessed through
	std::visit_format_arg
	or the visit member functions of std::basic_format_arg
	(since C++26).

Member functions
	format	formats the referenced object with the given contexts
	(C++20) (public member function)

     std::basic_format_arg<Context>::handle::format

	void	format(     std::basic_format_parse_context<Context::char_type>&
     (since
	parse_ctx,
     C++20)
		     Context& format_ctx ) const;

	Let

	  * T be the type of the formatting argument,
	  * TD be std::remove_const_t<T>,
	  *  TQ be const TD if const TD satisfies __formattable_with<Context> or
     TD
	    otherwise, and
	  * ref be a reference to the formatting argument.

	Equivalent to: typename Context::template formatter_type<TD> f;
	parse_ctx.advance_to(f.parse(parse_ctx));
	format_ctx.advance_to(f.format(const_cast<TQ&>(static_cast<const
     TD&>(ref)),
	format_ctx));

Notes
	A handle has reference semantics for the formatted argument and does not
     extend its
	lifetime. It is the programmer's responsibility to ensure that the argu-
     ment outlives
	the handle. Usually, a handle is only used within formatting functions.

See also
	basic_format_arg  class template that provides access  to  a  formatting
     argument for
	(C++20) 	  user-defined formatters
			  (class template)
	make_format_args   creates  a type-erased object referencing all format-
     ting arguments,
	make_wformat_args convertible to format_args
	(C++20) 	  (function template)
	(C++20)

http://cppreference.com 	   2024.06.10	   std::basic_..._arg::handle(3)
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