The PIXMISIS and FROMPIXM drivers will not work with the default parameters passed to them during the initialization routine used by IG_ISIS_drv_load_init_pipe(), and so they cannot be loaded, initialized, and linked by using this function. You must use separate
IG_ISIS_drv_load(), IG_ISIS_drv_init(), and IG_ISIS_drv_link() calls.

Unloading Drivers without Unlinking

It is not safe to unload drivers without first unlinking them, and it is bad programming practice to do so. If a linked driver remains in memory and is used after its child or sibling is gone, the pipe is in an unstable state. The driver will forward its data to an undetermined location, causing unpredictable results. You unlink drivers by linking the first driver with a null or 0.

// Unlink the two drivers by linking the hScan driver with a 0.
IG_ISIS_drv_link(hScan, 0);
IG_ISIS_drv_unload(hFileWriter);
IG_ISIS_drv_unload(hScan);