The library is completely asynchronous. This means that a call to a library function returns immediately, always. Operations that take time to complete are scheduled for background execution and return a handle to the operation. The rascal_isok function must first be used on these handles to make sure that the operation has been successfully scheduled. Any of the following actions can then be performed:
Cancel the operation by calling the rascal_cancel function.
Store the handle for later use.
Ignore the handle, if no interaction with the request is planned.