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

SPT_WRITEUPDATEUNLOCKX(2) OSS System Calls Reference Manual
Use on files opened for nowait I/O
• If the buffer is in an extended data segment, you cannot deallocate or
reduce the size of the extended data segment before the I/O completes
with a call to the Guardian AWAITIOX procedure or is canceled by a
call to the SPT_CANCEL() function or the Guardian CANCELREQ
procedure.
• 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 segment. It is the application’s
responsibility to ensure this.
• If you initiated the I/O with SPT_WRITEUPDATEUNLOCKX(), the
I/O must be completed with a call to the Guardian AWAITIOX pro-
cedure.
• 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_WRITEUPDATEUNLOCKX() can be
canceled with a call to SPT_CANCEL( ) or CANCELREQ. 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.
Bounds checking
If the extended address of buffer is odd, bounds checking rounds the address to
the next lower word boundary and also checks an extra byte. The odd address is
used for the transfer.
All considerations for SPT_WRITEUPDATEX() also apply to this call.
Use on OSS Objects
This procedure operates only on Guardian objects. If an OSS file is specified, Guardian file-
system error 2 occurs.
RETURN VALUES
The SPT_WRITEUPDATEUNLOCKX() 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_WRITEUPDATEX(2), SPT_WRITEX(2).
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