Guardian Procedure Calls Reference Manual

FILE_READUPDATE64_ Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameters
Returned Value
Considerations
Disk File Considerations
Interprocess Communication Considerations
Related Programming Manuals
Summary
The FILE_READUPDATE64_ procedure reads data from a disk or process file in anticipation of a
subsequent write to the file. FILE_READUPDATEL64_ is intended for use with 64-bit extended
addresses. The data buffer for FILE_READUPDATEL64_ can be either in the caller's stack segment
or any extended data segment.
• Disk files
FILE_READUPDATEL64_ is used for random processing. Data is read from the file at the position
of the current-record pointer. A call to this procedure typically follows a corresponding call to
FILE_SETPOSITION_ (or POSITION) or FILE_SETKEY_ (or KEYPOSITION[X]). The values of the
current- and next-record pointers do not change with the call to FILE_READUPDATEL64_].
• Queue Files
FILE_READUPDATEL64_ is not supported on queue files. An attempt to use
FILE_READUPDATEL64_ will be rejected with error 2.
• Interprocess communication
FILE_READUPDATEL64_ reads a message from the $RECEIVE file that is answered in a later
call to FILE_REPLY64_. Each message read by FILE_READUPDATEL64_ must be replied to in
a corresponding call to FILE_REPLY64_.
FILE_READUPDATE64_ extends the capabilities of the READUPDATE[X|XL] procedures in several
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 the returned count-read argument to reside outside of the 32-bit addressable
range.
NOTE: The FILE_READUPDATEL64_ 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.
486 Guardian Procedure Calls (F)