NB Approve Shutdown

The NBApproveShutdown callback function can be used by an application to put the system in a safe state before an application update, configuration update, or reboot event occurs. For example, closing active TCP sockets, ensuring Flash and/or file system write operations are complete, and putting critical peripherals in a safe state. The NBApproveShutdown() function as a weak reference to a system function that always returns true by default. If an application creates it's own function using the same signature, that function will be used instead.

A reason for the reboot request is passed to the function. The system will automatically call NBapproveShutdown() for the following reasons:

#define SHUTDOWN_CODEUPDATE         (1)   // A code update is requested
#define SHUTDOWN_CONFIGURE_REBOOT   (2)   // Configuration values have been modified with a requested reboot

An application can choose to ignore the parameters or add it's own. For custom reasons, the application should call NBApproveShutdown() with the appropriate reason:

// Custom reboot reason. System reasons start at 1, so pick something much larger
#define SHUTDOWN_CUSTOM_REBOOT 100
 
if( NBApproveShutdown(SHUTDOWN_CUSTOM_REBOOT))
{
     OSTimeDly(TICKS_PER_SECOND * 5);
     ForceReboot();
}

This example provides a serial port menu with options enable or disable a reboot for application or settings updates. For testing purposes you can select reboot from the serial menu, or attempt an application code update.