View source for RxUsbRegisterDeviceNotification

==Description==
Registers semaphores for attach/detach notification of specific USB devices. 

==Syntax==
''To register semaphores for attach/detach notification of specific USB devices use:''
<pre>
rc = RxUsbRegisterDeviceNotification(NotifyID,hDevAdd,hDevRem,idVendor,idProduct)
</pre>
''To register semaphores for attach/detach notification of even more specific USB devices use:''
<pre>
rc = RxUsbRegisterDeviceNotification(NotifyID,hDevAdd,hDevRem,idVendor,idProduct,bcdDevice) 
</pre>

==Parameters==
; NotifyID : the name of the variable to receive the Notification Identifier. 

; hDevAdd : the handle of the event semaphore to be posted on device attach. 

; hDevRem : the handle of the event semaphore to be posted on device detach. 

; idVendor : the Vendor Identifier (VendorID) from the device descriptor. 

; idProduct : the Product Identifier (ProductID) from the device descriptor. 

; bcdDevice : the Device Release Number from the device descriptor. 

==Return Code==
<pre>
0x0000 - NO_ERROR
</pre>
===Errors===
<pre>
0x0006 - ERROR_INVALID_HANDLE
0x0057 - ERROR_INVALID_PARAMETER
0x005F - ERROR_INTERRUPT
0x0064 - ERROR_TOO_MANY_SEMAPHORES
0x0067 - ERROR_TOO_MANY_SEM_REQUESTS
0x0069 - ERROR_SEM_OWNER_DIED
0x1B58 - USB_NOT_INIT
0x1B59 - USB_ERROR_NO_MORE_NOTIFICATTIONS
</pre>
==Remarks==
Device attach/detach notifications may be obtained by registering event
semaphores to be posted upon attach/detach of USB devices.
The RexxUtil library provides functions to work with event semaphores.
Some of these are used in the example code.

==Example Code==
<pre>
/* add SysCreateEventSem */
rc = RxFuncAdd('SysCreateEventSem','RexxUtil','SysCreateEventSem')
say '+SysCreateEventSem(),RC=0x'd2x(rc)

/* invoke SysCreateEventSem() */
hSemAttach = SysCreateEventSem()
say '*SysCreateEventSem(),RC=0x'd2x(rc)
hSemDetach = SysCreateEventSem()
say '*SysCreateEventSem(),RC=0x'd2x(rc)

/* drop SysCreateEventSem */
rc = RxFuncDrop('SysCreateEventSem')
say '-SysCreateEventSem(),RC=0x'd2x(rc)

/* add RxUsbRegisterDeviceNotification */
rc = RxFuncAdd('RxUsbRegisterDeviceNotification','usbcalls','RxUsbRegisterDeviceNotification')
say '+RxUsbRegisterDeviceNotification(),RC=0x'd2x(rc)

/* invoke RxUsbRegisterDeviceNotification */
idVendor=x2d(046D) /* vendor identifier */
idProduct=x2d(0804) /* product identifier */
bcdDevice=x2d(0009) /* device release number */
hDevAdd = hSemAttach; /* attach semaphore handle */
hDevRem = hSemDetach; /* detach semaphore handle */
drop NotifyID /* to receive the notification identifier */
rc = RxUsbRegisterDeviceNotification(NotifyID,hDevAdd,hDevRem,idVendor,idProduct,bcdDevice)
say '*RxUsbRegisterDeviceNotification(),RC=0x'd2x(rc)

/* drop RxUsbRegisterDeviceNotification */
rc = RxFuncDrop('RxUsbRegisterDeviceNotification')
say '-RxUsbRegisterDeviceNotification(),RC=0x'd2x(rc)

/* add SysWaitEventSem */
rc = RxFuncAdd('SysWaitEventSem','RexxUtil','SysWaitEventSem')
say '+SysWaitEventSem(),RC=0x'd2x(rc)

/* invoke SysWaitEventSem() */
timeout = 8000; /* await 8 seconds */
rc = SysWaitEventSem(hSemAttach,timeout)
say '*SysWaitEventSem(),RC=0x'd2x(rc)
if (rc=0) then say 'obtained Attach Notification'
rc = SysWaitEventSem(hSemDetach,timeout)
say '*SysWaitEventSem(),RC=0x'd2x(rc)
if (rc=0) then say 'obtained Detach Notification'

/* drop SysWaitEventSem */
rc = RxFuncDrop('SysWaitEventSem')
say '-SysWaitEventSem(),RC=0x'd2x(rc)
</pre>

==Related Functions==

[[Category:USBCalls]]