Namespaces
Variants

std:: vprint_nonunicode, std:: vprint_nonunicode_buffered

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< cpp ‎ | io
C++
Input/output library
Print functions
Print functions
(C++23)
(C++23)
(C++23) (C++23)
vprint_nonunicode vprint_nonunicode_buffered
(C++23) (C++23)
Defined in header <print>
void vprint_nonunicode ( std:: FILE * stream,
std:: string_view fmt, std:: format_args args ) ;
(1) (since C++23)
void vprint_nonunicode_buffered
( std:: FILE * stream, std:: string_view fmt, std:: format_args args ) ;
(2) (since C++23)
void vprint_nonunicode_buffered
( std:: string_view fmt, std:: format_args args ) ;
(3) (since C++23)

Format args according to the format string fmt , and writes the result to the output stream.

1) While holding the lock on stream , writes the character representation of formatting arguments provided by args formatted according to specifications given in fmt to stream .
If stream is not a valid pointer to an output C stream, the behavior is undefined.
2) Equivalent to std:: string out = std:: vformat ( fmt, args ) ;
std :: vprint_nonunicode ( stream, "{}" , std:: make_format_args ( out ) ) ; .
3) Equivalent to std :: vprint_nonunicode_buffered ( stdout , fmt, args ) .


After writing characters to the output stream, establishes an observable checkpoint .

(since C++26)

Contents

Parameters

stream - output file stream to write to
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-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

Exceptions

Notes

Feature-test macro Value Std Feature
__cpp_lib_print 202207L (C++23) Formatted output
202403L (C++26)
(DR23) 		Unbuffered formatted output
202406L (C++26)
(DR23) 		Enabling unbuffered formatted output for more formattable types
__cpp_lib_format 202207L (C++23) Exposing std::basic_format_string

Example

This section is incomplete
Reason: no example

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
P3107R5 C++23 printing operations were always buffered provides unbuffered printing operations
P3235R3 C++23 the names of the functions added
by P3107R5 were misleading 		changed the function names

See also

(C++23)
prints to Unicode capable stdout or a file stream using type-erased argument representation
(function)
(C++23)
outputs character data using type-erased argument representation
(function)
(C++23)
prints to stdout or a file stream using formatted representation of the arguments
(function template)
(C++20)
stores formatted representation of the arguments in a new string
(function template)