The
fgetwln ();
function
returns a pointer to the next line from the stream referenced by
Fa stream .
This line is
not
a standard wide character string as it does not end with a terminating
null wide character.
The length of the line, including the final newline,
is stored in the memory location to which
Fa len
points.
(Note, however, that if the line is the last
in a file that does not end in a newline,
the returned text will not contain a newline.)
RETURN VALUES
Upon successful completion a pointer is returned;
this pointer becomes invalid after the next
I/O
operation on
Fa stream
(whether successful or not)
or as soon as the stream is closed.
Otherwise,
NULL
is returned.
The
fgetwln ();
function
does not distinguish between end-of-file and error; the routines
feof(3)
and
ferror(3)
must be used
to determine which occurred.
If an error occurs, the global variable
errno
is set to indicate the error.
The end-of-file condition is remembered, even on a terminal, and all
subsequent attempts to read will return
NULL
until the condition is
cleared with
clearerr(3).
The text to which the returned pointer points may be modified,
provided that no changes are made beyond the returned size.
These changes are lost as soon as the pointer becomes invalid.
ERRORS
Bq Er EBADF
The argument
Fa stream
is not a stream open for reading.
The
fgetwln ();
function
may also fail and set
errno
for any of the errors specified for the routines
mbrtowc(3),
realloc(3),
or
read(2).
