Tribblix: manual page: fgetwc.3c

FGETWC(3C) Standard C Library Functions FGETWC(3C)

NAME

fgetwc, fgetwc_l - get a wide-character code from a stream

SYNOPSIS

#include <stdio.h>
#include <wchar.h>

wint_t fgetwc(FILE *stream);

#include <stdio.h>
#include <wchar.h>
#include <xlocale.h>

wint_t fgetwc_l(FILE *stream, locale_t, loc);

DESCRIPTION

The fgetwc() and fgetwc_l() functions 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). Whereas fgetwc()
uses the current locale, fgetwc_l() uses the locale specified by loc.

If an error occurs, the resulting value of the file position
indicator for the stream is indeterminate.

The fgetwc() and fgetwc_l() functions may mark the st_atime field of
the file associated with stream for update. The st_atime field will
be marked for update by the first successful execution of fgetwc(),
fgetc(3C), fgets(3C), fgetws(3C), fread(3C), fscanf(3C), getc(3C),
getchar(3C), gets(3C), or scanf(3C) using stream that returns data
not supplied by a prior call to ungetc(3C) or ungetwc(3C).

RETURN VALUES

Upon successful completion both functions return the wide-character
code of the character read from the input stream pointed to by stream
converted to a type wint_t.

For standard-conforming (see standards(7)) applications, if the end-
of-file indicator for the stream is set, fgetwc() and fgetwc_l()
return WEOF whether or not the stream is at end-of-file.

If a read error occurs, the error indicator for the stream is set,
fgetwc() and fgetwc_l() returns WEOF and sets errno to indicate the
error.

If an encoding error occurs, the error indicator for the stream is
set, fgetwc() and fgetwc_l() return WEOF, and errno is set to
indicate the error.

ERRORS

The fgetwc() and fgetwc_l() functions will fail if data needs to be
read and:

EAGAIN The O_NONBLOCK flag is set for the file descriptor underlying
stream and the process would be delayed in the fgetwc() or
fgetwc_l() operation.

EBADF The file descriptor underlying stream is not a valid file
descriptor open for reading.

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 process is ignoring or
blocking the SIGTTIN signal or the process group is orphaned.

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() and fgetwc_l() functions may fail if:

ENOMEM Insufficient memory is available.

ENXIO A request was made of a non-existent device, or the request
was outside the capabilities of the device.

EILSEQ The data obtained from the input stream does not form a valid
character.

USAGE

The ferror(3C) or feof(3C) functions must be used to distinguish
between an error condition and an end-of-file condition.

ATTRIBUTES