std::println(std::ostream)(3)

NAME
std::println(std::ostream) - std::println(std::ostream)

Synopsis
   Defined in header <ostream>
   template< class... Args >
   void println( std::ostream& os, std::format_string<Args...> fmt, (1) (since C++23)
   Args&&... args );
   void println( std::ostream& os ); (2) (since C++26)
   Formats args according to the format string fmt with appended '\n' (which means that
   each output ends with a new-line), and inserts the result into os stream.
   1) Equivalent to: std::print(os, "{}\n", std::format(fmt, args...));
   2) Equivalent to: std::print(os, "\n");
   The behavior is undefined if std::formatter<Ti, char> does not meet the
   BasicFormatter requirements for any Ti in Args (as required by
   std::make_format_args).

Parameters
   os - output stream to insert data into
             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
                        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.
             arg-id -
                        The arg-id s in a format string must all be present or all
                        be omitted. Mixing manual and automatic indexing is an
                        error.
   fmt - the format specification defined by the std::formatter
             format-spec - specialization for the corresponding argument. Cannot start
                        with }.
               * 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 range types, the format specification is interpreted
                 as range format specification.
               * For std::pair and std::tuple, the format specification
                 is interpreted as tuple format specification.
               * For std::thread::id and std::stacktrace_entry, see (since C++23)
                 thread id format specification and stacktrace entry
                 format specification.
               * For std::basic_stacktrace, no format specifier is
                 allowed.
               * For std::filesystem::path, see path format (since C++26)
                 specification.
               * For other formattable types, the format specification is determined by
                 user-defined formatter specializations.
   args... - arguments to be formatted

Return value
   (none)

Exceptions
     * std::bad_alloc on allocation failure.
     * Propagate any exception thrown by any formatter, e.g. std::format_error, without
       regard to the value of os.exceptions() and without turning on ios_base::badbit
       in the error state of os.
     * May throw ios_base::failure caused by os.setstate(ios_base::badbit) which is
       called if an insertion into os fails.

Notes
   Although overload (2) is added in C++26, all known implementations make it available
   in C++23 mode.
   Feature-test macro Value Std Feature
   __cpp_lib_print 202207L (C++23) Formatted output
   __cpp_lib_format 202207L (C++23) Exposing std::basic_format_string

Example
    This section is incomplete
    Reason: no example

See also
   print(std::ostream) outputs formatted representation of the arguments
   (C++23) (function template)
   println same as std::print except that each print is terminated by
   (C++23) additional new line
                       (function template)
   format stores formatted representation of the arguments in a new string
   (C++20) (function template)

Category:
     * Todo no example