i have index.pl and subs.pl when i run the program user inserts date of birth and then it is passed to getage() subroutine in subs.pl . subs.pl has many subroutines. getage() than implicitly calls another subroutine called validate() which validates the date entered by user.

when i run the index.pl user enters the date as: 03-04-2005

following error comes :can't modify non-lvalue subroutine call at subs.pl line 85, <> line 1

and at 85th line of subs.pl i have

list(my $val,my @value) = validate($dob);

why such error comes

any solutions