On Fri, 27 Jan 2017 16:47:40 +0000 Bruce Richardson <bruce.richard...@intel.com> wrote:
> On Fri, Jan 27, 2017 at 08:33:46AM -0800, Stephen Hemminger wrote: > > On Fri, 27 Jan 2017 09:57:03 -0500 > > Aaron Conole <acon...@redhat.com> wrote: > > > > > diff --git a/lib/librte_eal/common/include/rte_eal.h > > > b/lib/librte_eal/common/include/rte_eal.h > > > index 03fee50..46e427f 100644 > > > --- a/lib/librte_eal/common/include/rte_eal.h > > > +++ b/lib/librte_eal/common/include/rte_eal.h > > > @@ -159,7 +159,29 @@ int rte_eal_iopl_init(void); > > > * function call and should not be further interpreted by the > > > * application. The EAL does not take any ownership of the memory > > > used > > > * for either the argv array, or its members. > > > - * - On failure, a negative error value. > > > + * - On failure, -1 and rte_errno is set to a value indicating the > > > cause > > > + * for failure. > > > + * > > > + * The error codes returned via rte_errno: > > > + * EACCES indicates a permissions issue. > > > + * > > > + * EAGAIN indicates either a bus or system resource was not > > > available, > > > + * try again. > > > + * > > > + * EALREADY indicates that the rte_eal_init function has already been > > > + * called, and cannot be called again. > > > + * > > > + * EINVAL indicates invalid parameters were passed as argv/argc. > > > + * > > > + * EIO indicates failure to setup the logging handlers. This is > > > usually > > > + * caused by an out-of-memory condition. > > > + * > > > + * ENODEV indicates memory setup issues. > > > + * > > > + * ENOTSUP indicates that the EAL cannot initialize on this system. > > > + * > > > + * EUNATCH indicates that the PCI bus is either not present, or is > > > not > > > + * readable by the eal. > > > */ > > > int rte_eal_init(int argc, char **argv); > > > > Why use rte_errno? > > Most DPDK calls just return negative value on error which corresponds to > > error number. > > Are you trying to keep ABI compatibility? Doesn't make sense because before > > all these > > errors were panic's no working application is going to care. > > Either will work, but I actually prefer this way. I view using rte_errno > to be better as it can work in just about all cases, including with > functions which return pointers. This allows you to have a standard > method across all functions for returning error codes, and it only > requires a single sentinal value to indicate error, rather than using a > whole range of values. The problem is DPDK is getting more inconsistent on how this is done. As long as error returns are always same as kernel/glibc errno's it really doesn't matter much which way the value is returned from a technical point of view but the inconsistency is sure to be a usability problem and source of errors.
