Don't let Gaston hear you call it a Glock a DA. He insists on calling it Safe Action. In reality, it's a pre-tensioned constant-action intermediate between DA and SA. We really need a new term.
Unfortunately for you and Gaston, the BATF, who feel they are the ultimate authority on such matters and may kill your household peets and family members if you disagree with them, call the Glocks *double action.* Oh, and btw, Gaston also refers to all his products as GLOCK, with all uppercase letters.
The BATFE are wrong on this, regardless of their feelings on the matter.