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4.41 getwchar, getwchar_unlocked—read a wide character from standard input

Synopsis 

     #include <wchar.h>
     wint_t getwchar(void);
     
     #define _GNU_SOURCE
     #include <wchar.h>
     wint_t getwchar_unlocked(void);
     
     #include <wchar.h>
     wint_t _getwchar_r(struct _reent *reent);
     
     #include <wchar.h>
     wint_t _getwchar_unlocked_r(struct _reent *reent);

Description
getwchar function or macro is the wide character equivalent of the getchar function. You can use getwchar to get the next wide character from the standard input stream. As a side effect, getwchar advances the standard input's current position indicator.

getwchar_unlocked is a non-thread-safe version of getwchar. getwchar_unlocked may only safely be used within a scope protected by flockfile() (or ftrylockfile()) and funlockfile(). This function may safely be used in a multi-threaded program if and only if they are called while the invoking thread owns the (FILE *) object, as is the case after a successful call to the flockfile() or ftrylockfile() functions. If threads are disabled, then getwchar_unlocked is equivalent to getwchar.

The alternate functions _getwchar_r and _getwchar_unlocked_r are reentrant versions of the above. The extra argument reent is a pointer to a reentrancy structure.
Returns
The next wide character cast to wint_t, unless there is no more data, or the host system reports a read error; in either of these situations, getwchar returns WEOF.

You can distinguish the two situations that cause an WEOF result by using `ferror(stdin)' and `feof(stdin)'.
Portability
getwchar is required by C99.

getwchar_unlocked is a GNU extension.