FWIDE(3) Linux Programmer s Manual FWIDE(3)
NAME fwide - set and determine the orientation of a FILE stream
SYNOPSIS #include <wchar.h>
int fwide(FILE *stream, int mode);
DESCRIPTION When mode is zero, the fwide() function determines the current orienta- tion of stream. It returns a value > 0 if stream is wide-character ori- ented, i.e. if wide character I/O is permitted but char I/O is disal- lowed. It returns a value < 0 if stream is byte oriented, i.e. 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).
Once a stream has an orientation, it cannot be changed and persists until the stream is closed.
When mode is non-zero, the fwide() function first attempts to set stream s orientation (to wide-character oriented if mode > 0, or to byte oriented if mode < 0). It then returns a value denoting the cur- rent orientation, as above.
RETURN VALUE The fwide() function returns the streams orientation, after possibly changing it. A return value > 0 means wide-character oriented. A return value < 0 means byte oriented. A return value of zero means undecided.
CONFORMING TO ISO/ANSI C, POSIX.1-2001.
SEE ALSO fprintf(3), fwprintf(3)
NOTES Wide-character output to a byte oriented stream can be performed through the fprintf() function with the %lc and %ls directives.
Char oriented output to a wide-character oriented stream can be per- formed through the fwprintf() function with the %c and %s directives.
GNU 1999-11-17 FWIDE(3)