std::formatted_size

 

C++

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Utilities library

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Formatting library

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format (C++20)

format_to (C++20)

format_to_n (C++20)

formatted_size (C++20)

vformat (C++20)

vformat_to (C++20)

Formatter

formatter (C++20)

basic_format_parse_contextformat_parse_contextwformat_parse_context (C++20)(C++20)(C++20)

basic_format_contextformat_contextwformat_context (C++20)(C++20)(C++20)

Formatting arguments

basic_format_arg (C++20)

basic_format_argsformat_argswformat_argsformat_args_t (C++20)(C++20)(C++20)(C++20)

visit_format_arg (C++20)

make_format_argsmake_wformat_args (C++20)(C++20)

Format error

format_error (C++20)

 

Defined in header <format>
template<class... Args> std::size_t formatted_size(std::string_view fmt, const Args&... args);	(1)	(since C++20)
template<class... Args> std::size_t formatted_size(std::wstring_view fmt, const Args&... args);	(2)	(since C++20)
template<class... Args> std::size_t formatted_size(const std::locale& loc, std::string_view fmt, const Args&... args);	(3)	(since C++20)
template<class... Args> std::size_t formatted_size(const std::locale& loc, std::wstring_view fmt, const Args&... args);	(4)	(since C++20)

Determine the total number of characters in the formatted string by formatting args according to the format string fmt. If present, loc is used for locale-specific formatting.

The behavior is undefined if std::formatter<Ti, CharT> does not meet the Formatter requirements for each Ti in Args.

Parameters

fmt	-	string view representing the format string. The format string consists of ordinary characters (except { and }), which are copied unchanged to the output, escape sequences {{ and }}, which are replaced with { and } respectively in the output, and replacement fields. Each replacement field has the following format: introductory { character; (optional) arg-id, a non-negative number; (optional) a colon (:) followed by a format specification; final } character. arg-id specifies the index of the argument in args whose value is to be used for formatting; if arg-id is omitted, the arguments are used in order. The arg-ids in a format string must all be present or all be omitted. Mixing manual and automatic indexing is an error. The format specification is defined by the std::formatter specialization for the corresponding argument. For basic types and standard string types, the format specification is interpreted as standard format specification. For chrono types, the format specification is interpreted as chrono format specification. For other formattable types, the format specification is determined by user-defined formatter specializations.
args...	-	arguments to be formatted
loc	-	std::locale used for locale-specific formatting

Return value

The total number of characters in the formatted string.

Exceptions

Throws std::format_error if fmt is not a valid format string for the provided arguments. Also propagates any exception thrown by formatter.