I'm curious about handling signals in a background worker. As I understand it, these are blocked when the BGW is born, until enabled with BackgroundWorkerUnblockSignals() after possible customization.
Is there a known, default behavior that some signals will have, if I simply BackgroundWorkerUnblockSignals() without customizing? Will SIGINT and SIGTERM, for example, have default handlers that interact with the volatile flags in miscadmin.h that are used by CHECK_FOR_INTERRUPTS, and set the process latch? I notice that the worker_spi example code customizes SIGHUP and SIGTERM, giving them handlers that set a (different, local to the module) volatile flag, and set the process latch. The example code does call CHECK_FOR_INTERRUPTS, though I assume this won't detect ProcDie at all, now that the custom SIGTERM handler is setting a different, local flag. Perhaps it still does something useful with QueryCancel? Does this use of a custom SIGTERM handler, setting a custom flag, setting the process latch, and then checked in custom code, accomplish something important that would not be accomplished by a generic handler and CHECK_FOR_INTERRUPTS ? I'm just not clearly grasping the reason it's customized here. -Chap
