Specifications

Operating System Routines
IOC$CANCELIO
Description
IOC$CANCELIO cancels I/O to a device in the following device-independent
manner:
1. It confirms that the device is busy by examining the device-busy bit in the
UCB status longword (UCB$V_BSY in UCB$L_STS).
2. It confirms that the IRP in progress on the device originates from the current
process (that is, the contents of IRP$L_PID and PCB$L_PID are identical).
3. It confirms that the specified channel-index number is the same as the value
stored in the IRP’s channel-index field (IRP$W_CHAN).
4. It sets the cancel-I/O bit in the UCB status longword (UCB$V_CANCEL in
UCB$L_STS).
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