fwide(3) Library Functions Manual fwide(3) fwide - FILE C (libc, -lc) #include int fwide(FILE *stream, int mode); glibc (. feature_test_macros(7)): fwide(): _XOPEN_SOURCE >= 500 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L When mode is zero, the fwide() function determines the current orientation of stream. It returns a positive value if stream is wide-character oriented, that is, if wide-character I/O is permitted but char I/O is disallowed. It returns a negative value if stream is byte oriented--that is, if char I/O is permitted but wide-character I/O is disallowed. It returns zero if stream has no orientation yet; in this case the next I/O operation might change the orientation (to byte oriented if it is a char I/O operation, or to wide-character oriented if it is a wide-character I/O operation). , , , . mode , fwide() stream ( , mode 0, , mode 0). , , . fwide() . . . 0 . C11, POSIX.1-2008. POSIX.1-2001, C99. , , fprintf(3) %lc %ls. , , fwprintf(3) %c %s. fprintf(3), fwprintf(3) () Azamat Hackimov , Dmitry Bolkhovskikh , Yuri Kozlov , Kirill Rekhov ; GNU (GNU General Public License - GPL, 3 ) , - . - , , () () () <>. Linux 6.15 17 2025 . fwide(3)