because with 3 ? exactly 3 scalar arguments are expected and you only pass one

> if there is a way of doing it.

As already explained you could pass an array @values which is initialized with something like @values=($a,$b,$c)

> the way I am trying to do it

are you probably trying to code like in Tcl where (IIRC) comma space separated strings and arrays belong to the same data type? That's not Perl, sorry.