Date: Mon, 2 Feb 2009 11:58:09 -0800 From: Andrew Thompson <thompsa@FreeBSD.org> To: Christoph Mallon <christoph.mallon@gmx.de> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: write-only variables in src/sys/ - possible bugs Message-ID: <20090202195809.GA54528@citylink.fud.org.nz> In-Reply-To: <49874CA8.5090605@gmx.de> References: <49874CA8.5090605@gmx.de>
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On Mon, Feb 02, 2009 at 08:42:32PM +0100, Christoph Mallon wrote: > Hi, > > I compiled a list of all local variables in src/sys/ (r188000), which are > only written to, but never read. This is more than the GCC warning, which > only complains about variables, which are only declared (and maybe > initialised) and not used otherwise. In contrast this list contains > variables with the following usage pattern: > > int w = 42; // GCC warns about this ... > int x; // ... but not this > x = 23; > x++; > return 0; > > The list contains about 700 entries. About three dozen concern variables > named 'error'. Here's one *example* from the list: > > sys/dev/kbdmux/kbdmux.c:1304 > > In the function kbdmux_modevent() the variable 'error' is assigned values > eight times, but at the end of the function there is just a return 0; and > the variable is never read. Probably the value should be returned. > > You can find the list here: > http://tron.homeunix.org/unread_variables.log > > The list was generated by cparser, a C99 compiler, which uses libFIRM for > optimisation and code generation (lang/cparser in the ports). This is helpful, my only nit would be to run it through sort. :) Andrew
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