FPUTWC(3) Linux Programmer's Manual FPUTWC(3)
fputwc, putwc - write a wide character to a FILE stream
wint_t fputwc(wchar_t wc, FILE *stream);
wint_t putwc(wchar_t wc, FILE *stream);
The fputwc() function is the wide-character equivalent of the fputc(3) function. It
writes the wide character wc to stream. If ferror(stream) becomes true, it returns WEOF.
If a wide-character conversion error occurs, it sets errno to EILSEQ and returns WEOF.
Otherwise it returns wc.
The putwc() function or macro functions identically to fputwc(). It may be implemented as
a macro, and may evaluate its argument more than once. There is no reason ever to use it.
For nonlocking counterparts, see unlocked_stdio(3).
The fputwc() function returns wc if no error occurred, or WEOF to indicate an error. In
the event of an error, errno is set to indicate the cause.
Apart from the usual ones, there is
EILSEQ Conversion of wc to the stream's encoding fails.
The behavior of fputwc() depends on the LC_CTYPE category of the current locale.
In the absence of additional information passed to the fopen(3) call, it is reasonable to
expect that fputwc() will actually write the multibyte sequence corresponding to the wide
fgetwc(3), fputws(3), unlocked_stdio(3)
This page is part of release 3.55 of the Linux man-pages project. A description of the
project, and information about reporting bugs, can be found at
GNU 2013-04-19 FPUTWC(3)