what does this construct do {flag = flag | a;}?

[pnguine]

I'm trying to reuse some old code I wrote and forget where I found the syntax(I'm no expert - probably fit better in the 'dabbler' category).

if(pmIn != ""){flag = flag | a;}

Is this a short cut for the ternary operator? As in

flag = (pmIn != "") ? flag : a

or

if(pmIn != ""){flag = flag;} else {flag = a;}

Thanks