8. Processes
8 Processes
8.1 Creating an Erlang Process
An Erlang process is lightweight compared to threads and processes in operating systems.
A newly spawned Erlang process uses 309 words of memory in the non-SMP emulator without HiPE support. (SMP support and HiPE support both add to this size.) The size can be found as follows:
Erlang (BEAM) emulator version 5.6 [async-threads:0] [kernel-poll:false]
Eshell V5.6 (abort with ^G)
1> Fun = fun() -> receive after infinity -> ok end end.
#Fun<...>
2> {_,Bytes} = process_info(spawn(Fun), memory).
{memory,1232}
3> Bytes div erlang:system_info(wordsize).
309 The size includes 233 words for the heap area (which includes the stack). The garbage collector increases the heap as needed.
The main (outer) loop for a process must be tail-recursive. Otherwise, the stack grows until the process terminates.
