Messages in this thread | | | Date | Mon, 7 Nov 2005 12:02:57 -0800 | From | Greg KH <> | Subject | Re: typedefs and structs [was Re: [PATCH 16/42]: PCI: PCI Error reporting callbacks] |
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On Mon, Nov 07, 2005 at 01:36:00PM -0600, linas wrote: > On Mon, Nov 07, 2005 at 11:02:45AM -0800, Greg KH was heard to remark: > > > > > I'm not to clear on what "sparse" can do; however, in the good old days, > > > gcc allowed you to commit great sins when passing "struct blah *" to > > > subroutines, whereas it stoped you cold if you tried the same trick > > > with a typedef'ed "blah_t *". This got me into the habit of turning > > > all structs into typedefs in my personal projects. Can we expect > > > something similar for the kernel, and in particular, should we start > > > typedefing structs now? > > > > No, never typedef a struct. That's just wrong. > > Its a defacto convention for most C-language apps, see, for > example Xlib, gtk and gnome.
The kernel is not those projects.
> Also, "grep typedef include/linux/*" shows that many kernel device > drivers use this convention.
They are wrong and should be fixed.
See my old OLS paper on all about the problems of using typedefs in kernel code.
> > gcc should warn you > > just the same if you pass the wrong struct pointer > > There were many cases where it did not warn (I don't remember > the case of subr calls). I beleive this had to do with ANSI-C spec > issues dating to the 1990's; traditional C is weakly typed. > > Its not just gcc; anyoe who coded for a while eventually discovered > that tyedefs where strongly typed, but "struct blah *" were not.
Sorry, but you are using a broken compiler if it doesn't complain about this.
thanks,
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