Hey there,
I don't know which statement exactly causes the error. Last time I had this I accidentally changed parameters of the find_and_update - function. Now I finally can reproduce it =).
Hope this is helpful,
Armin

// codesnippets

{{ mongocxx::options::find_one_and_update TheOptions {};
TheOptions.sort(vieOptions);

std::cout
<< "78 - Find:\n" << bsoncxx::to_json(vieFind) << "\n"
<< "78 - Update:\n" << bsoncxx::to_json(vieUpdate) << "\n"
<< "78 - Options.sort:\n" << bsoncxx::to_json(vieOptions)
<< std::endl;

... collJobs.find_one_and_update(vieFind,vieUpdate,TheOptions);}}

src/bson/bson.c:2193 bson_get_data(): precondition failed: bson
process died.

// consol:

78 - Find:
{
"CServer" : {
"error" : false,
"dateEndLeadworker" :

{ "$exists" : true }

,
"dateStartConversion" :

{ "$exists" : false }

}
}

78 - Update:
{
"$set" : {
"CServer" : {
"dateStartConversion" :

{ "$date" : 1479621781745 }

,
"machineConversion" : "MyMachine_f29a8bc8aee611e6a05f0024d74d9538"
}
}
}

78 - Options.sort:
{
"CServer" :

{ "dateEntry" : 1 }

}

// Stacktrace:

{{__GI_raise (sig=6, sig@entry=6)
__GI_abort ()
bson_get_data ()
(anonymous namespace)::find_and_modify(_mongoc_collection_t*, bsoncxx::v_noabi::view_or_value<bsoncxx::v_noabi::document::view, bsoncxx::v_noabi::document::value>, _mongoc_find_and_modify_opts_t const*) ()
mongocxx::v_noabi::collection::find_one_and_update(bsoncxx::v_noabi::view_or_value<bsoncxx::v_noabi::document::view, bsoncxx::v_noabi::document::value>, bsoncxx::v_noabi::view_or_value<bsoncxx::v_noabi::document::view, bsoncxx::v_noabi::document::value>, mongocxx::v_noabi::options::find_one_and_update const&) () }}