Kernel prepatch 3.11-rc4 [LWN.net]

Kernel prepatch 3.11-rc4

Posted Aug 6, 2013 9:55 UTC (Tue) by khim (subscriber, #9252)
In reply to: Kernel prepatch 3.11-rc4 by error27
Parent article: Kernel prepatch 3.11-rc4

Also this should trigger an unreachable code warning...

You would not believe how often similar code is used in metaprogramming to strip away code which is not needed in some cases because we are using regular variable and not something more complex.

Sure, new warnings are added to compiler but that's not an easy process: even simple things like open(2) do something like this in modern system (try to look on /usr/include/bits/fcntl2.h in your system sometime, you'll be surprised to see how open(2) is implemented in modern GlibC).

Kernel prepatch 3.11-rc4

Posted Aug 10, 2013 11:15 UTC (Sat) by kleptog (subscriber, #1183) [Link] (1 responses)

I had a look and indeed, open(2) is implemented quite differently from what I expected. It implements error checking on the arguments and there's even a (not very well documented) __errordecl() function which allows you to add new error messages to gcc. I can probably find a use for that.

Thanks for the tip.

Kernel prepatch 3.11-rc4

Posted Aug 10, 2013 11:38 UTC (Sat) by khim (subscriber, #9252) [Link]

Small correction: __errordecl is not function, it's a macro defined in /usr/include/sys/cdefs.h and there are also similar __warndecl ...