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println(std::ostream)

From cppreference.com
< cpp‎ | io‎ | basic ostream
 
 
 
 
Defined in header <ostream>
template< class... Args >
  void println( std::ostream& os, std::format_string<Args...> fmt, Args&&... args );
(since C++23)

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.

Equivalent to: std::print(os, "{}\n", std::format(fmt, std::forward<Args>(args)...));

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).

Contents

[edit] Parameters

os - output stream to insert data into
fmt - 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-ids 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.
  • 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

[edit] Return value

(none)

[edit] Exceptions

[edit] Notes

Feature-test macro Value Std Comment
__cpp_lib_print 202207L (C++23) Formatted output
__cpp_lib_format 202207L (C++23) Exposing std::basic_format_string

[edit] Example

[edit] See also

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