!REGION: procedures for accessing parts (regions) of files

%externalroutinespec access file(%string(255)filename,%integer mode,
                             %integername ref,size)
%externalroutinespec deaccess file(%integer ref)
%externalroutinespec read region(%integer ref,byte,bytes,%bytename buffer)
%externalroutinespec write region(%integer ref,byte,bytes,%bytename buffer)
%endoffile

! ACCESS FILE
! Opens the file and returns in SIZE the number of bytes in the file,
! and in REF a token (actually the filestore transaction number) which
! must be passed to DEACCESS FILE, READ REGION, and WRITE REGION.
! MODE=0: Read-only, MODE=1: Read-modify.

! DEACCESS FILE
! Just closes the file

! READ/WRITE REGION
! Reads/writes BYTES bytes from/to the file specified by REF to/from
! store at BUFFER, starting with byte BYTE of the file
! (BYTE=0 means beginning of file).