getwc, getwc_unlocked, fgetwc, getwchar - Get a wide character
from an input stream
#include <stdio.h> #include <wchar.h>
wint_t getwc(
FILE *stream ); wint_t getwc_unlocked(
FILE *stream ); wint_t fgetwc(
FILE *stream ); #include <wchar.h>
wint_t getwchar(
void );
Standard C Library (libc)
Interfaces documented on this reference page conform to
industry standards as follows:
fgetwc(), getwc(), getwchar(): XSH5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Specifies an input stream from a file.
The fgetwc() function gets the next character from the
input stream specified by the stream parameter, converts
it to a wide-character code, and advances the associated
file position indicator for the stream. If an error
occurs, the file position indicator is indeterminate. This
function also marks the st_atime field of the file associated
with stream for update.
The getwc() function performs the same function as
fgetwc() but can be implemented as a macro on implementations
that conform to X/Open standards.
The getwchar() function gets the next wide character from
the standard input stream. This function is equivalent to
getwc(stdin).
The getwc_unlocked() function is functionally identical to
the getwc() function, except that getwc_unlocked() may be
safely used only within a scope that is protected by the
flockfile() and funlockfile() functions used as a pair.
The caller must ensure that the stream is locked before
these functions are used.
On return from calls to the preceding functions, applications
should use ferror() and feof() to distinguish
between error and end-of-file conditions.
Because getwc() can be implemented as a macro, applications
should not use it with a stream argument that is an
expression with side effects (for example, getwc(*f++)).
The fgetwc() function is recommended over getwc() for
reading characters from a stream associated with a file.
If the value returned by the getwchar() function is stored
into a variable of type wchar_t and then compared to the
macro WEOF (defined as type wint_t in the wchar.h header
file), the comparison may never succeed.
These functions return either the resultant wide-character
code or, for error and end-of-file conditions, the constant
WEOF (wide-character End-Of-File).
If any of the following conditions occur, the fgetwc(),
getwc(), getwc_unlocked(), and getwchar(), functions set
errno to the corresponding value: The O_NONBLOCK option is
set for the file descriptor underlying the stream parameter
and the process would be delayed by the read operation.
The file descriptor underlying the stream parameter
is not a valid file descriptor open for reading. The data
obtained from the input stream does not form a valid wide
character in the current locale. The read operation was
interrupted by a signal that was caught, and no data was
transferred. One of the following errors occurred: The
call is attempting to read from the process's controlling
terminal and either the process is ignoring or blocking
the SIGTTIN signal or the process group is orphaned. A
physical I/O error occurred. This condition is defined
starting with XSH Issue 4, Version 2. Insufficient memory
is available for the operation. The device associated
with stream either does not exist or cannot handle the
request. The file is a regular file and an attempt was
made to read at or beyond the offset maximum associated
with the corresponding stream.
Functions: fopen(3), fread(3), fgetws(3), getc(3),
gets(3), putwc(3), scanf(3), wscanf(3)
Standards: standards(5)
getwc(3)
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