Just starting working with Sybase 12.5 open client/C library, it seems
that many library functions do not restore the original pthread
cancellation state, but rather leave it in the disabled state.

So far I've found the following functions that disable thread
cancellation: ct_connect, ct_send. Is there any way to force a
different behaviour?

Thanks.

Hello,

I think you should log a case with Sybase technical support
so that a bug can be pursued. They won't have much experience
with this topic (in fact you are the first person ever to
mention it) so you might want modify one of the sample programs
in $SYBASE/$SYBASE_OCS/sample/ctlibrary to illustrate your point.

I ran this past a Sybase engineer and he stated this is something
that could be improved as they have not fully implemented cancellation
points in the product.

Currently, none of our libraries are cancellation safe. You should
expect possible havoc if the program cancels a thread within Sybase
libraries. It could leak file descriptors or memory. This is the
reason that Sybase disabled cancellation in the Open Client libraries
except at very specific points.

You might be able to create a wrapper around each of the Open Client
library functions that disables/enables the cancellation state.

Thanks,
Neal

Thank you very much for your answer!!! I will certainly file an issue
with Sybase tech support as you suggest, even though it sounds like
they understand the nature of the problem and are working on it.

Thank you,
-Leo.

Hello,

I do think that engineering understands the problem but I don't
think it is a priority right now so I doubt they are working on
it. I could not find any existing bugs that describe the problem.

When there is a bug and a customer case tied to an issue, then
the problem gains visibility and can be scheduled with engineering.

Thanks,
Neal