---
title: registerHandler
framework: kernel
role: pseudoSymbol
path: kernel/iokerneldebugger/1812741-registerhandler
---

# registerHandler

Registers the target and the handler functions.

## Declaration

```occ
static void registerHandler(
 IOService *target, 
 IODebuggerTxHandler txHandler = 0, 
 IODebuggerRxHandler rxHandler = 0, 
 IODebuggerLinkStatusHandler linkUpHandler = 0, 
 IODebuggerSetModeHandler setModeHandler = 0); 
```

## Parameters

- `target`: The target object.
- `txHandler`: The transmit handler function. The null handler is registered if the argument is zero.
- `rxHandler`: The receive handler function. The null handler is
- `linkUpHandler`: The linkup handler function. The null handler is registered if the argument is zero.

## Overview

Overview This method is called by handleOpen() and handleClose() to register or unregister the target and its handler functions.

## See Also

### Miscellaneous

- [debugger](kernel/iokerneldebugger/1812543-debugger.md)
- [free](kernel/iokerneldebugger/1812554-free.md)
- [handleClose](kernel/iokerneldebugger/1812560-handleclose.md)
- [handleIsOpen](kernel/iokerneldebugger/1812565-handleisopen.md)
- [handleOpen](kernel/iokerneldebugger/1812573-handleopen.md)
- [init](kernel/iokerneldebugger/1812584-init.md)
- [kdpLinkStatusDispatcher](kernel/iokerneldebugger/1812595-kdplinkstatusdispatcher.md)
- [kdpReceiveDispatcher](kernel/iokerneldebugger/1812607-kdpreceivedispatcher.md)
- [kdpSetModeDispatcher](kernel/iokerneldebugger/1812616-kdpsetmodedispatcher.md)
- [kdpTransmitDispatcher](kernel/iokerneldebugger/1812631-kdptransmitdispatcher.md)
- [lock](kernel/iokerneldebugger/1812643-lock.md)
- [nullLinkStatusHandler](kernel/iokerneldebugger/1812653-nulllinkstatushandler.md)
- [nullRxHandler](kernel/iokerneldebugger/1812663-nullrxhandler.md)
- [nullSetModeHandler](kernel/iokerneldebugger/1812671-nullsetmodehandler.md)
- [nullTxHandler](kernel/iokerneldebugger/1812684-nulltxhandler.md)
- [powerStateDidChangeTo](kernel/iokerneldebugger/1812705-powerstatedidchangeto.md)
- [powerStateWillChangeTo](kernel/iokerneldebugger/1812727-powerstatewillchangeto.md)
- [signalDebugger](kernel/iokerneldebugger/1812763-signaldebugger.md)
- [unlock](kernel/iokerneldebugger/1812777-unlock.md)