Thus the application, using an increased sigset_t size, sets up an
sa_mask with bit 1500 set. A library, having only room for 1024
bits, is not able to save the entire set, and so only the low 1024
are saved and restored.
True, the compatibility is only one way. If you have a new application
that was compiled with the new library and include files that support
2048 signals, then yes, it won't work with an older libc that only
supports 1024 signals.
But symbol versioning is important, and it does solve the compatibility
issues in the important direction....
- Ted