std::vprint_unicode
Defined in header <print>
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void vprint_unicode( std::FILE* stream, std::string_view fmt, std::format_args args ); |
(1) | (since C++23) |
void vprint_unicode( std::string_view fmt, std::format_args args ); |
(2) | (since C++23) |
Format args
according to the format string fmt
, and writes the result to the stream.
Let out be a temporary string produced by formatting the arguments in args with std::vformat(fmt, args).
std::vprint_unicode(stdout, fmt, args);
The behavior is undefined if:
- stream is not a valid pointer to a C stream;
- out contains invalid Unicode code units.
Parameters
stream | - | output file stream to write to | ||||||||||||||||||||||||||||||||||||||||||
fmt | - |
Each replacement field has the following format:
1) replacement field without a format specification
2) replacement field with a format specification
| ||||||||||||||||||||||||||||||||||||||||||
args | - | arguments to be formatted |
Return value
(none)
Exceptions
- std::bad_alloc on allocation failure.
- std::system_error, if writing to the stream fails.
- Propagates any exception thrown by used formatters, e.g. std::format_error.
Notes
The C++ standard encourages the implementers to produce a diagnostic message if out contains invalid Unicode code units.
On POSIX, the stream refers to a terminal if the expression isatty(fileno(stream)) != 0 holds true (see POSIX documentation for isatty
, and fileno
).
On Windows, the stream refers to a terminal if the expression GetConsoleMode(_get_osfhandle(_fileno(stream))) returns nonzero (see Windows documentation for GetConsoleMode
, _get_osfhandle
, and _fileno
). The native Unicode API on Windows is WriteConsoleW
.
If invoking the native Unicode API requires transcoding, the invalid code units are substituted with U+FFFD
REPLACEMENT CHARACTER (see "The Unicode Standard Version 14.0 - Core Specification", Chapter 3.9).
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 |
Example
This section is incomplete Reason: no example |
See also
(C++23) |
prints to stdout or a file stream using type-erased argument representation (function) |
(C++23) |
performs Unicode aware output 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) |
External links
1. | Unicode |
2. | The Unicode Standard Version 14.0 - Core Specification |