dwm-flexipatch/patch/sizehints_ruled.c

void
checkfloatingrules(Client *c)
{
	const char *class, *instance;
	unsigned int i;
	const Rule *r;
	XClassHint ch = { NULL, NULL };

	XGetClassHint(dpy, c->win, &ch);
	class    = ch.res_class ? ch.res_class : broken;
	instance = ch.res_name  ? ch.res_name  : broken;

	for (i = 0; i < LENGTH(rules); i++) {
		r = &rules[i];
		if ((!r->title || strstr(c->name, r->title))
		&& (!r->class || strstr(class, r->class))
		&& (!r->instance || strstr(instance, r->instance)))
			c->isfloating = r->isfloating;
	}
	if (ch.res_class)
		XFree(ch.res_class);
	if (ch.res_name)
		XFree(ch.res_name);
}