Using Trap Handlers

The following three examples illustrate how to connect, disconnect, and get trap handlers in the ChorusOS operating system.

Example 13-5 Connecting a Trap Handler

A trap handler specified as a LAP handler can be connected to a given trap number by calling the primitive:

#include <exec/chTrap.h>
int svSysTrapHandlerConnect(
			unsigned int trapNumber,
			KnLapDesc *trapLapDesc
);						

This call returns K_OK if it is successful and returns a negative value if unsuccessful.

Example 13-6 Disconnecting a Trap Handler

A trap handler previously connected to a trap number with a call to svSysTrapHandlerConnect() can be disconnected by calling the primitive:

#include <exec/chTrap.h>
int svSysTrapHandlerDisconnect(
			unsigned int trapNumber,
			KnLapDesc *currentTrapLapDesc
);						

The value of currentTrapLapDesc can be K_CONNECTED_LAP. If this is not the case, the value must point to a LAP descriptor that is identical to the LAP desciptor currently connected to the trap number.

The function will K_OK if successful or a negative value if an error occurs.

Example 13-7 Getting a Trap Handler

A copy of the LAP descriptor corresponding to the trap handler that is currently connected to the trap number can be obtained by calling the primitive:

#include <exec/chTrap.h>
int svSysTrapHandlerGetConnected(
			unsigned int trapNumber,
			KnLapDesc *currentTrapLapDesc
);						

The function returns K_OK on success and K_EINVAL if an error occurs.