# Synchronous ABI and online-change lifecycle

There is no native worker thread in atMb 0.8. The existing 16-argument
`atMbCall_cext` ABI is retained, and every transport tick runs synchronously in
the PLC task that owns the IEC client or slave instance.

The C component uses fixed context pools, generation-checked handles and no
retained IEC pointers. Request values and results are copied through the ABI
buffers during the owning PLC call.

For online change, `FB_reinit` closes the native context first, clears the client
handle and all IEC request pointers, and resets active-request state. The next
PLC scan recreates the context using the current configuration. Slave blocks
close their listener before clearing their native handle.

The external ABI signature/API version remain unchanged. Component version is
0.5.0.0; IEC library version is 0.8.0.0.