RIO_OPEN - Open a direct access file

Description:

Open a direct access file with the specified access mode and record size. Return a file descriptor which can be used to access the file.

Invocation:

CALL RIO_OPEN( FILE, ACMODE, FORM, RECSZ, FD, STATUS )

Arguments:

FILE = CHARACTER $*$ ( $*$ ) (Given)

Expression giving the name of the file to be opened.

ACMODE = CHARACTER $*$ ( $*$ ) (Given)

Expression giving the required access mode. Valid modes are:
'READ' - Open the file READONLY. The file must exist.
'WRITE' - Create a new file and open it to write/read.
'UPDATE' - Open a file to read/write. The file must exist.
'APPEND' - Open a file to write/read. If the file does not already exist, create it. (APPEND has no other effect for direct access)

FORM = CHARACTER $*$ ( $*$ ) (Given)

Expression giving the required record formatting. 'FORMATTED' or 'UNFORMATTED'

RECSZ = INTEGER (Given)

Expression giving the record size in bytes. RECSZ is only used if ACMODE is 'WRITE' or 'APPEND'. If ACMODE is 'APPEND' and the file already exists, RECSZ must agree with the existing record size.

FD = INTEGER (Returned)

Variable to contain the file descriptor.

STATUS = INTEGER (Given and Returned)

The global status.