driver_kerl.cpp File Reference

An Erlang Port Driver. More...

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "erl_driver.h"
#include "ei.h"
#include "common_kerl.h"
#include "kerl.h"
#include "ei_extended.h"

Include dependency graph for driver_kerl.cpp:

Functions
static ErlDrvData	kerlDriverStart (ErlDrvPort port, char *buff)
static void	kerlDriverStop (ErlDrvData handle)
static void	doFree (void *state)
static void	kerlDriverMain (void *asyncData)
static void	kerlDriverOutput (ErlDrvData handle, char *buff, int bufflen)
static void	kerlDriverReadyAsync (ErlDrvData drvData, ErlDrvThreadData asyncData)
	DRIVER_INIT (kerl)
Variables
ErlDrvEntry	kerlDriverEntry

---

Detailed Description

An Erlang Port Driver.

Author:

Thomas Lorentsen, Sten Gruener

This contains code required to load a driver into Erlang allowing calls to be made to Player.

Erlang will initialize the driver allowing it to pass calls using Erlang Interface. This driver will wrap up the varibless passed from Erlang and pass it onto kerl.cpp which will allow robot control in player.

This driver runs concurrently.

Driver is explained: http://erlang.org/doc/man/driver_entry.html

---

Function Documentation

doFree

(

void *

state

)

[static]

Parameters:

state

is the data passed into the driver Not currently used but called at the end of a function call

DRIVER_INIT

(

kerl

)

Initialise erlang driver.

kerlDriverMain

(

void *

asyncData

)

[static]

Parameters:

asyncData

is the kerldata passed into the driver Contains the kerl main functions passed from the async driver. Decoding of the atoms passed from erlang is done here and decides what kerl function is needed to call. If no function can be called then an error is returned.

kerlDriverOutput	(	ErlDrvData	handle,
		char *	buff,
		int	bufflen
	)			[static]

Parameters:

	handle	pointer to the passed port information (todo: not sure ;))
	buff	erlang port input string
	bufflen	length of the input string Function calls to the driver go here before they run asynchronously. The memory has to be copied to avoid curruption and then a thread is spawned at the end.

kerlDriverReadyAsync	(	ErlDrvData	drvData,
		ErlDrvThreadData	asyncData
	)			[static]

Parameters:

	drvData	the driver data passed
	asyncData	the async data passed This function is called when a async thread has completed This function is called after an asynchronous call has completed. The asynchronous call is started with driver_async.

kerlDriverStart	(	ErlDrvPort	port,
		char *	buff
	)			[static]

Parameters:

	port	is the port
	buff	any commands passed

Returns:

the port on success

This is called when the driver is instantiated, when open_port/2 is called.

kerlDriverStop

(

ErlDrvData

handle

)

[static]

Parameters:

handle

data This is called when the port is closed

---

Variable Documentation

kerlDriverEntry

Initial value:

 {
        NULL,                       
        kerlDriverStart,                
        kerlDriverStop,         
        kerlDriverOutput,       
        NULL,                       
        NULL,                       
        "kerl",                     
        NULL,                       
        NULL,                       
        NULL,                       
        NULL,                       
        NULL,
        kerlDriverReadyAsync, 
        NULL,
        NULL,
        NULL
}

This is the driver entry definition and helps erlang to know how to talk to the driver. The variables change in here depending if it is async of not