[alsa-devel] [PATCH - alsa-lib 1/1] Introduce snd_seq_client_info_get_card_number, for getting the card number of a seq client on recent kernels

[Clemens Ladisch]

Adam Goode wrote:
>  /**
> + * \brief Get the card number of a client_info container
> + * \param info client_info container
> + * \return the card number, -1 if no card associated with this client, or -ENOSYS if the
> + *         kernel does not support reporting this field
> + */

-1 is used as an out-of-range value when enumerating cards.  However,
I don't think this convention can be applied here, because the return
value is also used for error codes, and -1 would correspond to -EPERM.

Squashing all error codes into -1 is not a good idea, so I think the
value -1 should be converted into an appropriate error code, probably
-ENXIO.


Regards,
Clemens