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CheckIO.md

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NAME

CheckIO -- get the status of an IORequest

SYNOPSIS

    result = CheckIO(iORequest)
    D0               A1

    BOOL CheckIO(struct IORequest *);

Links: IORequest

FUNCTION

This function determines the current state of an I/O request and returns FALSE if the I/O has not yet completed. This function effectively hides the internals of the I/O completion mechanism.

CheckIO() will NOT remove the returned IORequest from the reply port. This is best performed with WaitIO. If the request has already completed, WaitIO will return quickly. Use of the Remove function is dangerous, since other tasks may still be adding things to your message port; a Disable would be required.

This function should NOT be used to busy loop (looping until IO is complete). WaitIO is provided for that purpose.

INPUTS

iORequest - pointer to an I/O request block

RESULTS

result - NULL if I/O is still in progress. Otherwise D0 points to the IORequest block.

NOTE CheckIO can hang if called on an IORequest that has never been used. This occurs if LN_TYPE of the IORequest is set to "NT_MESSAGE". Instead simply set LN_TYPE to 0.

SEE ALSO

DoIO, SendIO, WaitIO, AbortIO