While playing around with sources and adding new type of poller i found a misconcept in the code wich i suggest to fix:

On server.c there is a switch  which assigns type of poller depending of type of process:
switch (thread_args.process_type)
        {
            case ZBX_PROCESS_TYPE_CONFSYNCER:
                threads[i] = zbx_thread_start(dbconfig_thread, &thread_args);
                break;
            case ZBX_PROCESS_TYPE_POLLER:
                poller_type = ZBX_PROCESS_TYPE_POLLER;
                thread_args.args = &poller_type;
                threads[i] = zbx_thread_start(poller_thread, &thread_args);
                break;
            case ZBX_PROCESS_TYPE_UNREACHABLE:
                poller_type = ZBX_PROCESS_TYPE_UNREACHABLE;
                thread_args.args = &poller_type;
                threads[i] = zbx_thread_start(poller_thread, &thread_args);
                break;
 
This however there are also poller types defined in dbcache.h
I suggest assigning instead of asigning

poller_type=ZBX_PROCESS_TYPE_UNREACHABLE;

do assignement of correct poller type:

poller_type = ZBX_POLLER_TYPE_UNREACHABLE