IO in Erlang¶
How a Driver Looks Like¶
A port driver is a C module with several functions defined (see ErlDrvEntry
in emulator/beam/erl_driver.h:
- Start/stop, finish, process exit/emergency close functions
- IO events (async/input/output)
- Timeout handler
- Call function, which passes commands to the port
- Control function, which changes options in the port
- Flush function, which ensures that all data is written
Making a Port Driver¶
Define an erl_drv_entry variable (a struct) and fill it with pointers to
callback functions.
You will need to cover things such as starting your driver,
stopping it, opening a port, sending commands and receiving data, and few other.
See also
BEAM Wisdoms: Interfacing Erlang with the Outer World
Load your port driver and register it in the system under a name
(add_driver_entry).
See also
Todo
this goes to indepth section
