Guardian Procedure Calls Reference Manual

FILE_WRITEUPDATE64_ Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameters
Returned Value
Considerations
Disk File Considerations
Magnetic Tape Considerations
Example
Related Programming Manuals
Summary
The FILE_WRITEUPDATE64_ procedure transfers data from an array in the application program
to a file. The data buffer for FILE_WRITEUPDATE64_ can be either in the caller's stack segment or
any extended data segment.
For disk files, FILE_WRITEUPDATE64_ has two functions:
• To alter the contents of the record at the current position
• To delete the record at the current position in a key-sequenced or relative file
FILE_WRITEUPDATE64_ is used for processing data at random. Data from the application process'
array is written in the position indicated by the setting of the current-record pointer. A call to this
procedure typically follows a corresponding call to the FILE_READ64_ or FILE_READUPDATE64_
procedure. The current-record and next-record pointers are not affected by FILE_WRITEUPDATE64_.
For magnetic tapes, FILE_WRITEUPDATE64_ is used to replace a record in an already written tape.
The tape is backspaced one record; the data from the application process' array is written in that
area.
FILE_WRITEUPDATE64_ extends the capabilities of WRITEUPDATEX in several ways:
• It permits the write 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 write more than 56kb in a single operation by widening
the write count to 32 bits..
• It allows the returned count-written 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_WRITEUPDATE64_ 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.
536 Guardian Procedure Calls (F)