Open System Services System Calls Reference Manual (G06.28+)

System Functions (s and S) SPT_WRITEX(2)
• You must not modify the buffer before
the I/O completes with a call to the
Guardian AWAITIOX procedure. This
restriction also applies to other
processes that might be sharing the seg-
ment. It is the application’s responsibil-
ity to ensure this.
• If the I/O has been initiated with
SPT_WRITE(), the I/O must be com-
pleted with a call to the Guardian
AWAITIOX procedure.
• A selectable extended data segment
containing the buffer need not be in use
at the time of the call to AWAITIOX.
• Nowait I/O initiated with
SPT_WRITEX() can be canceled with
a call to SPT_CANCEL() or CAN-
CELREQ. The I/O is canceled if the
file is closed before the I/O completes or
if the Guardian AWAITIOX procedure
is called with a positive time limit and
specific file number and the request
times out.
Interprocess Communication Consideration
Indication that the destination process is running
If the SPT_WRITEX() is to another process, successful com-
pletion of the SPT_WRITEX() call (or a Guardian AWAITIOX
procedure call if nowait) indicates that the destination process is
running.
RETURN VALUES
The SPT_WRITEX() 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: SPT_CANCEL(2), SPT_CONTROL(2), SPT_FILE_CLOSE_(2),
SPT_FILE_OPEN_(2), SPT_LOCKFILE(2), SPT_LOCKREC(2), SPT_READLOCKX(2),
SPT_READUPDATELOCKX(2), SPT_READUPDATEX(2), SPT_READX(2),
SPT_SETMODE(2), SPT_UNLOCKFILE(2), SPT_UNLOCKREC(2),
SPT_WRITEREADX(2), SPT_WRITEUPDATEUNLOCKX(2),
SPT_WRITEUPDATEX(2).
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