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5.4 Manipulation of files

Utility DEFDIR

SUBROUTINE DEFDIR( , , , )

INTEGER UNIT, IPGD, ILON, M(*)

It is advisable to call this utility after opening all the direct access files. In reality, it is only obligatory to call this utility before a call to modules using MEFDIR (manipulation of direct access files with the aid of utilities OUVDIR, LECDIR, ECRDIR, FERDIR, ..., is voluntarily omitted in this user guide). Since the implementation of the [Fortran 77] standard, it is possible to avoid the use of MEFDIR by using the OPEN, READ, WRITE and CLOSE commands directly.

UNIT

is the unit number of the file (only its absolute value is considered).

IPGD

is the largest page number that the file may contain.

ILON

is the length of a page in words.

M

is the super-array (unused).

Utility OUVRIR

SUBROUTINE OUVRIR( , , , , )

INTEGER UNIT, RECL, IOSTAT

CHARACTER*(*) FILE, SPEC

This utility opens a file (see also OUVRIS). The call to this utility ensures an improved portability than the direct use of the OPEN command.

UNIT

is the file unit number. In an OPEN command, this number appears after keyword UNIT.

FILE

is the file name. In an OPEN command, this name appears after keyword FILE, except if it equals ' '.

SPEC

is the list of specifications. In an OPEN command, the specifications appear after keywords STATUS, ACCESS, FORM, BLANK, where:

STATUS

= OLD, NEW, SCRATCH or UNKNOWN

ACCESS

= SEQUENTIAL or DIRECT

FORM

= FORMATTED or UNFORMATTED

BLANK

= NULL or ZERO

These specifications can be given in any order, separated by commas, blanks being ignored.

The default values are those of the [Fortran 77] standard:

STATUS

= UNKNOWN

ACCESS

= SEQUENTIAL

FORM

= FORMATTED if ACCESS = SEQUENTIAL, or UNFORMATTED if ACCESS = DIRECT

BLANK

= NULL

RECL

is the record length, in machine-units (see IINFO('RECL')). In an OPEN command, this length appears after keyword RECL.

IOSTAT

is the return code. In an OPEN command, this code appears after keyword IOSTAT. If no error occured at the opening, IOSTAT = 0.

An example of a call:

CALL OUVRIR(10, 'POBA.DIRECT', 'OLD, DIRECT', 1024, IOSTAT)

Utility OUVRIS

SUBROUTINE OUVRIS( , , , )

INTEGER UNIT, RECL

CHARACTER*(*) FILE, SPEC

This utility opens a file and stops execution in case of an error. It is therefore unnecessary for the programmer to do the following test:

CALL OUVRIR(UNIT,FILE,SPEC,RECL,IOSTAT)

IF (IOSTAT.NE.0) CALL ARRET(IOSTAT)

Utility TRUNIT

SUBROUTINE TRUNIT( )

INTEGER UNIT

This utility finds a free unit number, i.e. connected to no other file. It is often called before OUVRIR.