# $EPIC: isfilevalid.txt,v 1.2 2007/02/15 03:53:35 jnelson Exp $
======Synopsis:======
$[[isfilevalid]](//file descriptor//)

======Description:======
This function returns true if the //file descriptor// was previously 
returned by the [[open]] function and has not yet been passed to the 
[[close]] function, and false otherwise.

This will tell you whether or not it possible to [[read]] or [[write]]
to a file.

======Returns:======
<file>
 1   The file descriptor is valid and can be used.
 0   The file descriptor is not valid and cannot be used
</file>

======History:======
This function first appeared in EPIC4-1.1.6.