[cups] how to work around API changes?

[Collins, David]

Hi Mike,

If we are just using basic cups printing and haven't developed any api's is 2.0.4 stable and reliable compared to 1.4.2 ?  We are trying to make sure our environment has the latest patches in our large printing environment.

Thanks
David


-----Original Message-----
From: cups-bounces at cups.org [mailto:cups-bounces at cups.org] On Behalf Of Michael Sweet
Sent: Monday, August 31, 2015 6:10 AM
To: The CUPS user discussion list.
Subject: Re: [cups] how to work around API changes?

Jacob,

> On Aug 28, 2015, at 8:25 PM, Jacob Marble <jacobmarble at google.com> wrote:
>
> Context:
> The following change makes API changes, so my software has to support <1.6
> or >=1.6, but can't support both.
> STR #3928 Add accessors for IPP APIs and make IPP structures private.
>
> I need to support users who are building against older CUPS client APIs.
> The easy way is to copy the new accessor functions into my project
> (surrounded with #ifndef _CUPS_API_1_6), but that's a legal gray area.
>
> Is there a commonly-accepted way to do this?

The recommended "fix" for code like this is to define the following before including any CUPS headers:

    #define _IPP_PRIVATE_STRUCTURES

This has been in place since CUPS 1.6, and will likely remain in place for a while - our goal is not to make major changes to those structures (very unlikely) but to a) make it easier to access attribute values and b) make it safer to access attribute values.

As for importing the functions from the newer CUPS releases, that is NOT recommended since you'll end up with duplicate symbols when running the binary on newer systems, which can lead to unpredictable results when your code is in a shared library/loadable module.

If you want to move the code to the new accessor functions, you can define macros that stand in for the functions on older CUPS releases, and/or include renamed accessor functions.

_________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair

_______________________________________________
cups mailing list
cups at cups.org
https://www.cups.org/mailman/listinfo/cups

________________________________

The information contained in this message is privileged and intended only for the recipients named. If the reader is not a representative of the intended recipient, any review, dissemination or copying of this message or the information it contains is prohibited. If you have received this message in error, please immediately notify the sender, and delete the original message and attachments.