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

System Functions (s and S) SPT_READUPDATELOCKX(2)
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.
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