It is the $, yes. If you look further up in the file you’ll see that the definition is inside a quote. The $ signifies that the value of the following expression (ccdf, and pdecls..., pargs..., etc) from outside the quote should be inserted there. The variables ccdf, pfun, pargs, and pdecls are defined before the quote. The definition means that the fdistccdf is a call to a compiled function (via ccall).