Messages in this thread | | | Date | Sat, 19 Aug 2006 03:29:10 +0400 | From | Alexey Dobriyan <> | Subject | Re: Complaint about return code convention in queue_work() etc. |
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On Fri, Aug 18, 2006 at 05:43:18PM -0400, Jeff Garzik wrote: > Alan Stern wrote: > >I'd like to lodge a bitter complaint about the return codes used by > >queue_work() and related functions: > > > > Why do the damn things return 0 for error and 1 for success??? > > Why don't they use negative error codes for failure, like > > everything else in the kernel?!! > > It's a standard programming idiom: return false (0) for failure, true > (non-zero) for success. Boolean.
There are at least 3 idioms:
1) return 0 on success, -E on fail¹.
rv = foo(); if (rv < 0) ...
2) return 1 on YES, 0 on NO. 3) return valid pointer on OK, NULL on fail.
p = kmalloc(); if (!p) ...
#2 should only be used if condition in question is spelled nice:
if (license_is_gpl_compatible()) ... else ATI_you_can_fuck_off_too();
The question is into which category queue_work() fails.
> Certainly the kernel often uses the -errno convention, but it's not a rule.
¹ BSD returns E* where E* is negative and thus avoids "return E*;" bugs (where E is positive).
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