Re: [dpdk-dev] [PATCH 25/25] rte_eal_init: add info about rte_errno codes

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 27 Jan 2017 09:57:03 -0500
Aaron Conole <aconole@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.