[sane-devel] SANE2 standard revisited: sane_get_select_fd

[Oliver Rauch]

On Tuesday 10 December 2002 20:19, Matto Marjanovic wrote:

> A frontend which actually wants to guarantee a responsive user interfac=
e
>  must implement its own mechanism to circumvent blocking backends.
>  Once the frontend has this code, it no longer cares if there is suppor=
t
>  for non-blocking I/O or not.

We are just removing all possibilites for a frontend to keep the user=20
interface alive in a one-thread/one-process way by removing the select_fd=
 and=20
the non-blocking io-mode.

It is not a good API design for SANE when the frontend has to use threads=
 or=20
subprocesses to keep the userintaface alive while using sane functions. I=
=20
know that it is modern to use threads but that does not mean that it is t=
he=20
right approach to use it.

I suggest to keep it in the standard. It does not cost a lot for a backen=
d
to implement it, it does not cost anything for the API but it gives the=20
frontends more flexibility.

We are just creating a "SANE standard for poor people".
The idea of sane2 is to add more features and more flexibilty to sane.
We are calling it sane2 beacause we want some extensions that are
not compatible to sane1. In general the sane1 standard is not bad
and I do not see a reason to reinvent everyting and to re-program
everything. We should keep close to the sane1 standard when there
is no important reason to do a change.
Please also keep in mind that a sane2 frontend should be able
to handle sane1 backends.

Oliver

--=20
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