Open System Services System Calls Reference Manual (G06.28+, H06.05+)

System Functions (s and S) SPT_READUPDA
TELOCKX(2)
— You can cancel nowait I/O initiated with
SPT_READUPDATELOCKX() 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.
Use of buffers A file opened by SPT_FILE_OPEN_() uses direct I/O transfers by
default; you can use SPT_SETMODE(72) to force the system to use an
intermediate buffer in the process file segment (PFS) for I/O transfers.
Bounds checking
If the extended address of buffer is odd, bounds checking rounds the
address to the next lower word boundary and checks an extra byte as
well. The odd address is used for the transfer.
All considerations for the SPT_LOCKREC() function also apply to this function. See
also the "Disk File Considerations" for the Guardian READUPDATE procedure.
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_READUPDATELOCKX() 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_READUPDATEX(2), SPT_READX(2), SPT_SETMODE(2), SPT_UNLOCKFILE(2),
SPT_UNLOCKREC(2), SPT_WRITEREADX(2), SPT_WRITEUPDATEUNLOCKX(2),
SPT_WRITEUPDATEX(2), SPT_WRITEX(2).
STANDARDS CONFORMANCE
This function is an extension to the UNIX 98 specification. Interfaces documented on this refer-
ence page conform to the following industry standards:
— IEEE Std 1003.1c-1995, POSIX System Application Program Interface
The use of the header file spthread.h is an HP exception to the POSIX standard.
527186-007 Hewlett-Packard Company 7−247