код символа из потока (character code from a stream)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
fgetwc — get a wide-character code from a stream
Синопсис (Synopsis)
#include <stdio.h>
#include <wchar.h>
wint_t fgetwc(FILE *stream);
Описание (Description)
The functionality described on this reference page is aligned
with the ISO C standard. Any conflict between the requirements
described here and the ISO C standard is unintentional. This
volume of POSIX.1‐2017 defers to the ISO C standard.
The fgetwc() function shall obtain the next character (if
present) from the input stream pointed to by stream, convert that
to the corresponding wide-character code, and advance the
associated file position indicator for the stream (if defined).
If an error occurs, the resulting value of the file position
indicator for the stream is unspecified.
The fgetwc() function may mark the last data access timestamp of
the file associated with stream for update. The last data access
timestamp shall be marked for update by the first successful
execution of fgetwc(), fgetws(), fwscanf(), getwc(), getwchar(),
vfwscanf(), vwscanf(), or wscanf() using stream that returns data
not supplied by a prior call to ungetwc().
The fgetwc() function shall not change the setting of errno if
successful.
Возвращаемое значение (Return value)
Upon successful completion, the fgetwc() function shall return
the wide-character code of the character read from the input
stream pointed to by stream converted to a type wint_t. If the
end-of-file indicator for the stream is set, or if the stream is
at end-of-file, the end-of-file indicator for the stream shall be
set and fgetwc() shall return WEOF. If a read error occurs, the
error indicator for the stream shall be set, fgetwc() shall
return WEOF, and shall set errno to indicate the error. If an
encoding error occurs, the error indicator for the stream shall
be set, fgetwc() shall return WEOF, and shall set errno to
indicate the error.
Ошибки (Error)
The fgetwc() function shall fail if data needs to be read and:
EAGAIN The O_NONBLOCK flag is set for the file descriptor
underlying stream and the thread would be delayed in the
fgetwc() operation.
EBADF The file descriptor underlying stream is not a valid file
descriptor open for reading.
EILSEQ The data obtained from the input stream does not form a
valid character.
EINTR The read operation was terminated due to the receipt of a
signal, and no data was transferred.
EIO A physical I/O error has occurred, or the process is in a
background process group attempting to read from its
controlling terminal, and either the calling thread is
blocking SIGTTIN or the process is ignoring SIGTTIN or the
process group of the process is orphaned. This error may
also be generated for implementation-defined reasons.
EOVERFLOW
The file is a regular file and an attempt was made to read
at or beyond the offset maximum associated with the
corresponding stream.
The fgetwc() function may fail if:
ENOMEM Insufficient storage space is available.
ENXIO A request was made of a nonexistent device, or the request
was outside the capabilities of the device.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
The ferror() or feof() functions must be used to distinguish
between an error condition and an end-of-file condition.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
Section 2.5, Standard I/O Streams, feof(3p), ferror(3p),
fopen(3p)
The Base Definitions volume of POSIX.1‐2017, stdio.h(0p),
wchar.h(0p)
