[jplj]

De la ayuda de delphi:

Delphi syntax:

function Pos(Substr: string; S: string): Integer;

Description

In Delphi, Pos searches for a substring, Substr, in a string, S. Substr and S are string-type expressions.

Pos searches for Substr within S and returns an integer value that is the index of the first character of Substr within S. Pos is case-sensitive. If Substr is not found, Pos returns zero.