Utility: Get-File-Info - HP 9835A Programming Manual

164 I/O Handling
UTILITY: Get file info
General Procedure: The utility is given the file number and the location of a place to store the
file descriptor. It retrieves the designated descriptor and stores it, provided the file has been
assigned.
Special Requirements: There must be a ten-word area available for the utility to store the
information from the descriptor.
Call Procedure:
1. Load register A with the address of the ten-word area where you desire the information
to be stored.
2. Load register B with the file number (an integer from 1 to 10).
3. Call the utility.
Exit Conditions:
RET 1
Occurs if the file has not been assigned by a BASIC ASSIGN statement.
RET 2 Occurs if all went normally.
Here is an example of a routine which has a file number passed to it, and then gets the file
descriptor -
! ... ~
t:' ::::- =.. ;- .
• • • • • ;. '_\.",::1
,::,-:--,,::''''
!.. ...
Ui···i :::::F·