Introduce ddsrt_abort and ddsrt_exit

[poetinger]

This pull request:

• Introduces ddsrt_abort and ddsrt_exit
• Replaces abort with ddsrt_abort in ddsc, ddsrt, cdr, and ddsi
• Addes a symbol export test for each

[eboasson]

Thanks @poetinger, I do see the practical value of not calling abort() directly but putting something in between if one is using an embedded platform — at least I have found something of the sort useful in the past 🙂.

So that's the good bit.

The bad bit is that not all the aborts in the core code have been replaced, for example src/core/cdr/src/dds_cdrstream_keys.part.c have a bunch left.

Not replacing abort in all locations (like tests) is a defensible choice, but I think it only makes life more complicated to sometimes use abort and sometimes use ddsrt_abort: now one has to decide which one to use. So I think all should be replaced and only a single call to abort should remain, in ddsrt_abort.

The subject of exit is another story. Cyclone DDS comes in multiple parts: the core bit is a library—this should never terminate and so should never call exit to begin with, and it doesn't—and then there are some tools/examples/tests that use it. I don't quite see why something like ddsperf can't just call exit.

So unless you have a good argument why exit must be avoided at all cost, I'd take out the 11 changes related to it.

[poetinger]

Sounds reasonable to me. I'll remove ddsrt_exit and do another pass for missing aborts, including the ones in tests 👍.