[alsa-devel] Alsa-lib strings?

[Clemens Ladisch]

David Henningsson wrote:
> 1a) can I count on alsa-lib's strings (everything from card name and
>     mixer identifiers to various descriptions) to be UTF-8 or perhaps
>     even 7-bit?

Alsa-lib itself does not care about the encoding.

The strings are whatever the kernel uses.  In practice, this almost
always means ASCII, but kernel policy is UTF-8.  (At the moment, the
only way I know of to get a non-ASCII string is from a USB device.)

Alsa-lib can also return strings from configuration files.  These are
encoded in whatever the editor happens to use, i.e., in practice, UTF-8.

> 1b) In what way can buggy drivers violate the answers to 1a?

The USB driver is not buggy. :)  But in theory, you could get any random
crap.

For testing, you can change a card's "id" attribute in sysfs.

> 2) Can I count on the strings to be zero terminated?

In theory, yes.

> snd_ctl_elem_id_set_name

Oops!  Using strncpy() here is wrong.


Regards,
Clemens