Function findWindowClause

src/backend/parser/parse_clause.c:3840–3854

* findWindowClause * Find the named WindowClause in the list, or return NULL if not there */

 *		Find the named WindowClause in the list, or return NULL if not there
 */
static WindowClause *
findWindowClause(List *wclist, const char *name)
{
	ListCell   *l;

	foreach(l, wclist)
	{
		WindowClause *wc = (WindowClause *) lfirst(l);

		if (wc->name && strcmp(wc->name, name) == 0)
			return wc;
	}

	return NULL;
}

/*
 * transformFrameOffset