Thanks for your comments and yes I got your point, I know that undef $b will do, But I need to delete $b using $a, The typeglob itself need to be freed via $a without actually using $b. Have you got it now?.

You cant delete the typeglob while a reference to it still exists (from $a or $b). You can however make it undefined, (freeing up any IO handles etc attached to it) with the following:

undef *$a
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Dave.

You cant delete the typeglob while a reference to it still exists (fro
+m $a or $b). You can however make it undefined, (freeing up any IO ha
+ndles etc attached to it) with the following:
[download]

Thanks for giving me a solution, I have understood, but I have one more question, Let us consider the below code,

open $a, "/etc/passwd" or die "can't  open /etc/passwd: $!\n";
{
        local $/ = undef;
        $userdetails = <$a>;
        print ">>",$userdetails,"<<\n";
}
close($a); # this closes the filehandle
print "A>",$a ,"<\n";  # this prints a glob
# .... (assume that some lines of code lies here)
# ..

#########################################################
# in some other part of the program, How do I check whether
# the filehandle associated with the handle is still open?
# I have done it this way, if(defined fileno($a)),
# because fileno(filehandle) will return undef if there is
# no filehandle associated with it.
# Is any other ways exist to check the above problem?.
#########################################################
[download]

You probably want

if (!eof($a)) ...
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Dave.