Erlang has two kinds of 'function calls' (terminology used there is message passing):
- Synchronous calls where the caller will receive a response, and waits for X seconds until considering the message lost. Synchronous messages are blocking on the caller side, and block on the receiever while they are being processed.
- Asynchronous calls where the caller fires the message off and further semantics are undefined---the message could be ignored, lost, received, and acknowledged through a side channel, or a message back to the caller later on.
The Erlang runtime provides a framework--OTP as in online telecom protocol referencing its always on, phones must work at all times roots--that lets you set up supervisors, watchers, and handlers to deal with the problem of trying to send messages to processes that aren't there, child processes disappearing on you, and so forth.
Erlang's ecosystem aims for a 'soft realtime' setup, where usefulness degrades but is not totally lost---so the default option on failure is to retry until some kind of success threshold is reached.
- Synchronous calls where the caller will receive a response, and waits for X seconds until considering the message lost. Synchronous messages are blocking on the caller side, and block on the receiever while they are being processed.
- Asynchronous calls where the caller fires the message off and further semantics are undefined---the message could be ignored, lost, received, and acknowledged through a side channel, or a message back to the caller later on.
The Erlang runtime provides a framework--OTP as in online telecom protocol referencing its always on, phones must work at all times roots--that lets you set up supervisors, watchers, and handlers to deal with the problem of trying to send messages to processes that aren't there, child processes disappearing on you, and so forth.
Erlang's ecosystem aims for a 'soft realtime' setup, where usefulness degrades but is not totally lost---so the default option on failure is to retry until some kind of success threshold is reached.