chars_waiting
chars_waiting — checks for characters waiting to be read on a file.
chars_waiting (file)
fileA file pointer to a previously opened file. This may be either a file in the file system, or a string opened for read and write.
The number of characters waiting on the open file.
This function determines whether there are any characters waiting to be
read on the given file. The file may be a string file (created by
open_string), in which case the number of
characters which have not yet been treated by a read or
similar call will be returned.
If chars_waiting is to be called on a file after it
has been partially read, the file must be unbuffered first with
unbuffer_file. Otherwise characters will be read in
buffer by buffer and held locally in groups of 1024. This will cause
chars_waiting to return unexpected results.
Gamma>ft = open("mytestfile.dat", "r");#<File:"mytestfile.dat">Gamma>unbuffer_file(ft);#<File:"mytestfile.dat">Gamma>chars_waiting(ft);9Gamma>char(read_char(ft));"A"Gamma>chars_waiting(ft);8Gamma>read_line(ft);"BCDEFGHI"Gamma>Gamma>x = open_string("hello");#<File:"String">Gamma>chars_waiting(x);5Gamma>char(read_char(x));"h"Gamma>chars_waiting(x);4Gamma>