On Thu, Oct 24, 2013 at 9:48 PM, Paul Zimmerman <Paul.Zimmerman@xxxxxxxxxxxx> wrote: >> From: Joe Perches [mailto:joe@xxxxxxxxxxx] >> Sent: Thursday, October 24, 2013 9:34 PM >> >> On Fri, 2013-10-25 at 03:52 +0000, Paul Zimmerman wrote: >> > > From: Dan Williams >> > > Sent: Thursday, October 24, 2013 12:45 AM >> > > >> > > On Thu, Oct 24, 2013 at 12:36 AM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: >> > > > Permit list_for_each redifinitions like: >> > > > >> > > > #define for_each_connector_peer(peer, port, c) \ >> > > > list_for_each_entry(peer, &(c)->ports, node) \ >> > > > if (port != peer) >> > > > >> > > > ...which triggers: >> > > > ERROR: Macros with complex values should be enclosed in parenthesis >> > >> > Kind of off-topic, but that macro looks a little dangerous. From what I have >> > seen in the kernel, it's usually done something like this: >> > >> > #define for_each_connector_peer(peer, port, c) \ >> > list_for_each_entry(peer, &(c)->ports, node) \ >> > if (port == peer) {} else >> >> That seems pretty non-standard. >> Look at include/linux/list.h or >> $ git grep -E "\{\s*\}\s*else" >> >> Is there any effective difference? > > I fail to see your point. There are no similar constructs in list.h that I > can see, and the output from git grep agrees with what I wrote. > > The difference is that with Dan's macro, this: > > if (foo) > for_each_connector_peer(peer, port, c) > bar(); > else > ... > > Will not interpreted by the compiler as the programmer intended. Ah yes, that would be nasty. Thanks. -- Dan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
