HelenOS sources

fputuc            776 uspace/lib/c/generic/io/io.c 	return fputuc(wc, stdout);
fputuc            127 uspace/lib/c/include/stdio.h extern wint_t fputuc(char32_t, FILE *);
fputuc            127 uspace/lib/posix/include/libc/stdio.h extern wint_t fputuc(char32_t, FILE *);