std::vprint_nonunicode,std::vprint_nonunicode_buffered

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[edit]

Input/output library

I/O manipulators
Print functions(C++23)
C-style I/O
Buffers
basic_streambuf
basic_filebuf
basic_stringbuf
basic_spanbuf (C++23)
strstreambuf (C++98/26*)
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ios_base
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basic_ostringstream
basic_stringstream
Array I/O
basic_ispanstream (C++23)
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basic_spanstream (C++23)
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ostrstream (C++98/26*)
strstream (C++98/26*)
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basic_osyncstream (C++20)
Types
streamoff
streamsize
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Error category interface
iostream_category (C++11)
io_errc (C++11)

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Print functions

Print functions
print (C++23)
println (C++23)
vprint_unicodevprint_unicode_buffered (C++23)(C++23)
vprint_nonunicodevprint_nonunicode_buffered (C++23)(C++23)

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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)

Formatargs according to the format stringfmt, and writes the result to the output stream.

1) While holding the lock onstream, writes the character representation of formatting arguments provided byargs formatted according to specifications given infmt tostream.

Ifstream is not a valid pointer to an output C stream, the behavior is undefined.

2) Equivalent tostd::string out=std::vformat(fmt, args);
std::vprint_nonunicode(stream,"{}",std::make_format_args(out));.

3) Equivalent tostd::vprint_nonunicode_buffered(stdout, fmt, args).

After writing characters to the output stream, establishes anobservable checkpoint.

(since C++26)

[edit]Parameters

stream - output file stream to write to

fmt

[edit]

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. Thearg-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 thestd::formatter specialization for the corresponding argument. Cannot start with}.

For basic types and standard string types, the format specification is interpreted asstandard format specification.
For chrono types, the format specification is interpreted aschrono format specification.

For range types, the format specification is interpreted asrange format specification.
Forstd::pair andstd::tuple, the format specification is interpreted astuple format specification.
Forstd::thread::id andstd::stacktrace_entry, seethread id format specification andstacktrace entry format specification.
Forstd::basic_stacktrace, no format specifier is allowed.

(since C++23)

Forstd::filesystem::path, seepath format specification.

(since C++26)

For other formattable types, the format specification is determined by user-definedformatter specializations.

args - arguments to be formatted

[edit]Exceptions

std::bad_alloc on allocation failure.
std::system_error, if writing to the stream fails.
Propagates any exception thrown by usedformatters, e.g.std::format_error.

[edit]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)	Exposingstd::basic_format_string

[edit]Example

This section is incomplete
Reason: no example

[edit]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 byP3107R5 were misleading	changed the function names

[edit]See also

vprint_unicodevprint_unicode_buffered (C++23)	prints to Unicode capablestdout or a file stream usingtype-erased argument representation (function)[edit]
vprint_nonunicode(std::ostream) (C++23)	outputs character data usingtype-erased argument representation (function)[edit]
print (C++23)	prints tostdout or a file stream usingformatted representation of the arguments (function template)[edit]
format (C++20)	stores formatted representation of the arguments in a new string (function template)[edit]