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    std::vformat

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    C++
     
    Text processing library
     
    Formatting library
    Standard format specification
    Formatting functions
    (C++20)
    (C++20)
    (C++20)
    (C++20)
    (C++20)
    (C++20)
    Format strings
    (C++20)(C++20)(C++20)
    (C++26)
    Formatting concepts
    (C++23)
    Formatter
    (C++20)
    (C++23)
    (C++23)
    (C++23)
    (C++23)
    (C++20)(C++20)(C++20)
    (C++20)(C++20)(C++20)
    (C++23)
    (C++23)
    Formatting arguments
    (C++20)
    (C++20)
    (C++20)(C++20)(C++20)
    (C++20) (deprecated in C++26)
    (C++20)(C++20)
    Format error
    (C++20)
     
    Defined in header <format> 
    std::string vformat(std::string_view fmt, std::format_args args);
    		(1) (since C++20) 
    std::wstring vformat(std::wstring_view fmt, std::wformat_args args);
    		(2) (since C++20) 
    std::string vformat(const std::locale& loc, std::string_view fmt, std::format_args args);
    		(3) (since C++20) 
    std::wstring vformat(const std::locale& loc, std::wstring_view fmt, std::wformat_args args);
    		(4) (since C++20)

    Format arguments held by args according to the format string fmt, and return the result as a string. If present, loc is used for locale-specific formatting.

    Parameters

    fmt - string view representing the format string.

    an object that represents 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:

    { arg-id (optional) } (1)
    { arg-id (optional) : format-spec } (2)
    1) replacement field without a format specification
    2) replacement field with a format specification
    arg-id - specifies the index of the argument in args whose value is to be used for formatting; if it is omitted, the arguments are used in order.

    The arg-id s in a format string must all be present or all be omitted. Mixing manual and automatic indexing is an error.

    format-spec - the format specification defined by the std::formatter specialization for the corresponding argument. Cannot start with }.

    (since C++23)
    (since C++26)
    • 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

    A string object holding the formatted result.

    Exceptions

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

    This section is incomplete
    Reason: the second sentence is not backed by the draft standard

    Example

    This section is incomplete
    Reason: no example

    See also