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Difference between revisions of "cpp/io/vprint nonunicode"

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< cpp‎ | io
m (→‎Top: rm copy-pasted statement — it is not applicable here directly; +fmt)
m (~)
 
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{{cpp/title|vprint_nonunicode}}
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{{cpp/title|vprint_nonunicode|vprint_nonunicode_buffered}}
 
{{cpp/io/print/navbar}}
 
{{cpp/io/print/navbar}}
  
 
{{dcl begin}}
 
{{dcl begin}}
 
{{dcl header|print}}
 
{{dcl header|print}}
−
{{dcl|num=1|since=c++23|1=
+
{{dcl|num=1|since=c++23|
 
void vprint_nonunicode( std::FILE* stream,
 
void vprint_nonunicode( std::FILE* stream,
 
                         std::string_view fmt, std::format_args args );
 
                         std::string_view fmt, std::format_args args );
 
}}
 
}}
−
{{dcl|num=2|since=c++23|1=
+
{{dcl|num=2|since=c++23|
−
void vprint_nonunicode( std::string_view fmt, std::format_args args );
+
void vprint_nonunicode_buffered( std::FILE* stream,
 +
                                std::string_view fmt, std::format_args args );
 +
}}
 +
{{dcl|num=3|since=c++23|
 +
void vprint_nonunicode_buffered( std::string_view fmt, std::format_args args );
 
}}
 
}}
 
{{dcl end}}
 
{{dcl end}}
  
−
Format {{tt|args}} according to the format string {{tt|fmt}}, and writes the result to the stream.
+
Format {{c|args}} according to the format string {{c|fmt}}, and writes the result to the output stream.
  
−
@1@ Writes the result of {{c|std::vformat(fmt, args)}} to the stream.
+
@1@ While holding the lock on {{c|stream}}, writes the character representation of formatting arguments provided by {{c|args}} formatted according to specifications given in {{c|fmt}} to {{c|stream}}.
−
The behavior is undefined if {{c|stream}} is not a valid pointer to a C stream.
+
@@ If {{c|stream}} is not a valid pointer to an output C stream, the behavior is undefined.
  
−
@2@ same as {{v|1}} when {{c|stream}} is equal to the text stream {{lc|stdout}}, i.e.
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@2@ Equivalent to: {{c multi
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{{c|std::vprint_nonunicode(stdout, fmt, args);}}.
+
|1=std::string out = std::vformat(fmt, args);
 +
|2=std::vprint_nonunicode(stream, "{}", std::make_format_args(out));
 +
}}
 +
 
 +
@3@ Equivalent to: {{c|std::vprint_nonunicode_buffered(stdout, fmt, args)}}.
  
 
===Parameters===
 
===Parameters===
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{{par|args|arguments to be formatted}}
 
{{par|args|arguments to be formatted}}
 
{{par end}}
 
{{par end}}
−
 
−
===Return value===
 
−
(none)
 
  
 
===Exceptions===
 
===Exceptions===
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===Notes===
 
===Notes===
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{{ftm begin|std=1|value=1}}
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{{ftm begin|std=1|value=1|comment=1}}
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{{ftm|std=C++23|value=202207L|__cpp_lib_print}}
+
{{ftm|__cpp_lib_print|Formatted output|value=202207L|std=C++23|rowspan=3}}
−
{{ftm|std=C++23|value=202207L|__cpp_lib_format}}
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{{ftm|-|Formatted output with stream locking|value=202403L|std=C++26|dr=23}}
 +
{{ftm|-|Enabling nonlocking formatter optimization for more formattable types|value=202406L|std=C++26|dr=23}}
 +
{{ftm|__cpp_lib_format|Exposing {{lc|std::basic_format_string}}|value=202207L|std=C++23}}
 
{{ftm end}}
 
{{ftm end}}
  

Latest revision as of 04:40, 4 July 2024

 
C++
 
Input/output library
 
Print functions
Print functions
(C++23)
(C++23)
(C++23)(C++23)
vprint_nonunicodevprint_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).

Contents

[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.

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

[edit] Exceptions

[edit] Notes

Feature-test macro Value Std Feature
__cpp_lib_print 202207L (C++23) Formatted output
202403L (C++26)
(DR23)		 Formatted output with stream locking
202406L (C++26)
(DR23)		 Enabling nonlocking formatter optimization for more formattable types
__cpp_lib_format 202207L (C++23) Exposing std::basic_format_string

[edit] Example

This section is incomplete
Reason: no example

[edit] See also

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