[erlang-questions] erts_port_control() and binp

[Salikhov Dinislam]

Hello!

I'm looking through VM sources now.
In erts/emulator/beam/erl_port.h there is a 'struct 
ErtsProc2PortSigData_' with a union as the last field.
One of the values of this union is 'struct control'.
I'm interesting in the field binp of the struct control.

I grepped through the sources and found that the struct is used only in 
a few places in erts/emulator/beam/io.c
Except the places where the field is set, it's used only as an argument 
of cleanup_scheduled_control() in the same file.
So what's the meaning of the field binp? What is it needed for?

Salikhov Dinislam