hi Dan,
On Wed, Apr 11, 2012 at 12:54 AM, Dan Carpenter <[email protected]> wrote: > On Tue, Apr 10, 2012 at 04:06:41PM -0600, Jim Cromie wrote: >> --- a/drivers/staging/media/as102/as102_usb_drv.c >> +++ b/drivers/staging/media/as102/as102_usb_drv.c >> @@ -367,7 +367,7 @@ static int as102_usb_probe(struct usb_interface *intf, >> ENTER(); >> >> /* This should never actually happen */ >> - if ((sizeof(as102_usb_id_table) / sizeof(struct usb_device_id)) != >> + if (ARRAY_SIZE(as102_usb_id_table) != >> (sizeof(as102_device_names) / sizeof(const char *))) { > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > I wonder why it missed this one? > > If you wanted to send a follow on patch you could just change this > to: > BUILD_BUG_ON(ARRAY_SIZE(as102_usb_id_table) != > ARRAY_SIZE(as102_device_names)); > >> pr_err("Device names table invalid size"); >> return -EINVAL; > > regards, > dan carpenter > My larger goal was to find use-cases for this: (sent to LKML a day or 2 ago) +/** + * BUILD_BUG_DECL - check declared objects + * @name: distinguishes multiple uses at same scope. + * @cond: false expr, typically like sizeof(a) != sizeof(b) + * + * This works at file-scope too, and supports checks like: + * BUILD_BUG_DECL(foo, sizeof(a) != sizeof(b)); + * BUILD_BUG_DECL(id_strings, ARRAY_SIZE(id_strings) != ARRAY_SIZE(id_vals)); + */ +#define BUILD_BUG_DECL(name, cond) \ + static __initdata struct { \ + int BUILD_BUG_DECL_ ## name[1 - 2*!!(cond)]; \ + } BUILD_BUG_DECL_ ##name[0] __attribute__((unused)) + It lets you check array consistency at compile-time, rather than waiting til run-time. Julia Lawall worked up a spatch script that patched a bunch of cases, all for file-scope static arrays. As such, it didnt find your case. Glancing at the context you quoted, it might be useful there ? Are there others too ? thanks Jim _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
