chars_waiting

Arguments

Returns

The number of characters waiting on the open file.

Description

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.

Example

Gamma> ft = open("mytestfile.dat", "r");
#<File:"mytestfile.dat">
Gamma> unbuffer_file(ft);
#<File:"mytestfile.dat">
Gamma> chars_waiting(ft);
9
Gamma> char(read_char(ft));
"A"
Gamma> chars_waiting(ft);
8
Gamma> read_line(ft);
"BCDEFGHI"
Gamma> 

Gamma> x = open_string("hello");
#<File:"String">
Gamma> chars_waiting(x);
5
Gamma> char(read_char(x));
"h"
Gamma> chars_waiting(x);
4
Gamma> 
		

See Also

open, open_string, unbuffer_file