OpenDevice

NAME

OpenDevice - Gain access to a device

SYNOPSIS

err = OpenDevice(deviceName, unitNum, iORequest, flags);
INT32 OpenDevice(STRPTR, UINT32, struct IORequest *, UINT32);

FUNCTION

This function opens the named device/unit and initializes the given
I/O request block.  Specific documentation on opening procedures
may come with certain devices.

All calls to OpenDevice should have matching calls to CloseDevice!

INPUTS

devName - requested device name

unitNumber - the unit number to open on that device.  The format of
	the unit number is device specific.  If the device does
	not have separate units, send a zero.

iORequest - the I/O request block to be returned with appropriate fields initialized.

flags - additional driver specific information. This is sometimes used to request opening a device with exclusive access.

SEE ALSO

[[CloseDevice]], [[AddDevice]], [[RemDevice]]

EXAMPLE

#include "exec_funcs.h"

void main(SysBase *SysBase)
{
	// We need a proper MessagePort to get Messages
	struct MsgPort *mp= CreateMsgPort();
	struct TimeRequest *io;
	
	// Now we need an IO Request Structure
	io = CreateIORequest(mp, sizeof(struct TimeRequest));
	if (io == NULL) 
	{
		DPrintF("Couldnt create IORequest (no Memory?)\n");
		DeleteMsgPort(mp);		
	}
	//Get Unit UNIT_VBLANK from device, this runs at 1/100 sec
	INT32 ret = OpenDevice("timer.device", UNIT_VBLANK, (struct IORequest *)io, 0);
	if (ret != 0)
	{
		DPrintF("OpenDevice Timer failed!\n");
		// Please tidy up, close all !
		DeleteIORequest((struct IORequest *)io);
		DeleteMsgPort(mp);
		return;
	}
	
	// Now we have everything setup.. Lets Proceed
	io->tr_node.io_Command = TR_ADDREQUEST; /* add a new timer request */
	io->tr_time.tv_micro = 0;	// 0 micros to wait
	io->tr_time.tv_secs = 5;		// 5 secs to wait

	// post request to the timer -- will go to sleep till done
	DPrintF("We will go 5 Seconds to sleep\n");
	DoIO((struct IORequest *) io );
	DPrintF("Return after 5 Seconds\n");

	CloseDevice(io);	
	DeleteIORequest((struct IORequest *)io);
	DeleteMsgPort(mp);
}