Open System Services System Calls Reference Manual (G06.29+, H06.08+, J06.03+)

System Functions (n - p) PUT_CANCEL(2)

Considerations

Queue files If a PUT_READUPDATELOCKX() function operation is canceled using the

PUT_CANCEL() function, the PUT_READUPDATELOCKX() call might

already have deleted a record from the queue ﬁle, which could result in the loss

of a record from the queue ﬁle. For audited queue ﬁles only, your application

can recover from a timeout error by calling the

PUT_ABORTTRANSACTION() function, when detecting Guardian ﬁle-

system error 40, to ensure that any dequeued records are reinserted into the ﬁle.

For nonaudited queue ﬁles, there is no recovery of a lost record. Thus, your

application should never call the Guardian AWAITIOX procedure with a time

limit greater than 0 (zero) if a PUT_READUPDATELOCKX() call is pending.

The PUT_ABORTTRANSACTION() recovery procedure does not work on

nonaudited queue ﬁles.

Messages The server process (that is, a process that was opened and to which the I/O

request was sent) receives a system message -38 (queued message cancellation)

that identiﬁes the canceled I/O request, if it has requested receipt of such mes-

sages. If the server has already replied to the I/O request, message -38 is not

delivered. For details about system message -38, see the Guardian Procedure

Errors and Messages Manual.

RETURN VALUES

The PUT_CANCEL() function returns 0 (zero) upon successful completion. Otherwise, this

function returns a nonzero Guardian ﬁle-system error number that indicates the outcome of the

operation.

For information about Guardian ﬁle-system error numbers, see the Guardian Procedure Errors

and Messages Manual.

ERRORS

None. This function does not set the errno variable.

RELATED INFORMATION

Functions: PUT_CONTROL(2), PUT_FILE_CLOSE_(2), PUT_FILE_OPEN_(2),

PUT_LOCKFILE(2), PUT_LOCKREC(2), PUT_READLOCKX(2),

PUT_READUPDATELOCKX(2), PUT_READUPDATEX(2), PUT_READX(2),

PUT_SETMODE(2), PUT_UNLOCKFILE(2), PUT_UNLOCKREC(2),

PUT_WRITEREADX(2), PUT_WRITEUPDATEUNLOCKX(2),

PUT_WRITEUPDATEX(2), PUT_WRITEX(2).

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