FGETWC
NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS CONFORMING TO SEE ALSO NOTES
fgetwc - read a wide character from a FILE stream
#include stream); wint_t getwc (FILE* stream);
The fgetwc function is the wide-character equivalent of the fgetc function. It reads a wide character from stream and returns it. If the end of stream is reached, or if ferror(stream) becomes true, it returns WEOF. If a wide character conversion error occurs, it sets errno to EILSEQ and returns WEOF.
The getwc function or macro functions identically to fgetwc. It may be implemented as a macro, and may evaluate its argument more than once. There is no reason ever to use it.
The fgetwc function returns the next wide-character from the stream, or WEOF.
Apart from the usual ones, there is
EILSEQ
The data obtained from the input stream does not form a valid character.
ISO/ANSI C, UNIX98
fputwc(3), fgetws(3), ungetwc(3)
The behaviour of fgetwc depends on the LC_CTYPE category of the current locale.
In the absence of additional information passed to the fopen call, it is reasonable to expect that fgetwc will actually read a multibyte sequence from the stream and then convert it to a wide character.
6 pages link to fgetwc(3):