Guardian Procedure Calls Reference Manual

FILE_READUPDATELOCK64_ Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameters
Returned Value
Considerations
OSS Considerations
Related Programming Manuals
Summary
The FILE_READUPDATELOCK64_ procedure is used for random processing of records in a disk
file. FILE_READUPDATELOCK64_ is intended for use with 64-bit extended addresses. The data
buffer for FILE_READUPDATELOCK64_ can be either in the caller's stack segment or any extended
data segment.
FILE_READUPDATELOCK64_ locks, then reads the record from the current position in the file in the
same manner as the combination of FILE_LOCKREC64_ and FILE_READUPDATE64_.
FILE_READUPDATELOCK64_ is intended for reading a record after calling FILE_SETPOSITION_
(or POSITION) or FILE_SETKEY_ (or KEYPOSITION[X]), possibly in anticipation of a subsequent
call to the FILE_WRITEUPDATE64_ or FILE_WRITEUPDATEUNLOCK64_ procedure.
A call to FILE_READUPDATELOCK64_ is functionally equivalent to a call to FILE_LOCKREC64_
followed by a call to FILE_READUPDATE64_. However, less system processing is incurred when
one call is made to FILE_READUPDATELOCK64_ rather than two separate calls to FILE_LOCKREC64_
and FILE_READUPDATE64_.
FILE_READUPDATELOCK64_ extends the capabilities of the READUPDATELOCKX procedure in the
following ways:
• It permits the read buffer to reside outside of the 32-bit addressable range.
• It is callable from both 32-bit and 64-bit processes.
• It allows for a future capability to read more than 56kb in a single operation by widening the
read count to 32 bits.
• It allows the returned count- read argument to reside outside of the 32-bit addressable
range.
• It allows a 64-bit nowait I/O tag to be passed.
• Rather than returning a condition code status, the procedure returns a file management error.
A return value of zero indicates success.
NOTE: The FILE_READUPDATELOCK64_ procedure is supported on systems running H06.24
and later H-series RVUs and J06.13 and later J-series RVUs. Its use is recommended for new code.
492 Guardian Procedure Calls (F)