FILE_UTILITY.F90 Subprograms

Last modified: Fri Feb 11 14:23:42 2005.

• GET_LUN
• FILE_EXISTS
• FILE_OPEN

Subprogram Descriptions

 NAME:
       Get_Lun

 PURPOSE:
       Function to obtain a free logical unit number for file access

 CALLING SEQUENCE:
       Lun = Get_Lun()

 INPUT ARGUMENTS:
       None.

 OUTPUT ARGUMENTS:
       None.

 FUNCTION RESULT:
       Lun:          Logical unit number that may be used for file access.
                     If Lun > 0 it can be used as a logical unit number to open
                                and access a file.
                        Lun < 0 a non-existant logical unit number was reached
                                during the search.
                     UNITS:      N/A
                     TYPE:       INTEGER
                     DIMENSION:  Scalar

 CALLS:
       None.

 SIDE EFFECTS:
       None known.

 RESTRICTIONS:
       None.

 PROCEDURE:
       The search for a free logical unit number begins at 10. The logical
       unit number is first tested to see if it exists. If it does not, the
       result is set to a negative value. If the file unit does exist, it is
       tested to see if it is connected to an open file. If so, it is
       incremented by 1. This is repeated until a free (or invalid) logical
       unit number is found.

(See File_Utility.f90)

 NAME:
       File_Exists

 PURPOSE:
       PUBLIC function to determine if a file unit or a file exists.

 CALLING SEQUENCE:
       Result = File_Exists( FileID/Filename )

 INPUT ARGUMENTS:
       Specify one of:

         FileID:     The logical unit number for which the existence
                     is to be determined.
                     UNITS:      N/A
                     TYPE:       INTEGER
                     DIMENSION:  Scalar
                     ATTRIBUTES: INTENT( IN )
       or

         Filename:   Name of the file the existence of which is to
                     be determined.
                     UNITS:      N/A
                     TYPE:       CHARACTER( * )
                     DIMENSION:  Scalar
                     ATTRIBUTES: INTENT( IN )

 OUTPUT ARGUMENTS:
       None.

 FUNCTION RESULT:
       Result:       The return value is a logical result.
                     If .TRUE.  the file unit/file exists.
                        .FALSE. the file unit/file does not exist.
                     UNITS:      N/A
                     TYPE:       LOGICAL
                     DIMENSION:  Scalar

 CALLS:
       None.

 SIDE EFFECTS:
       None known.

 RESTRICTIONS:
       None.

(See File_Utility.f90)

 NAME:
       File_Open

 PURPOSE:
       Function to determine if a file is open for I/O.

 CALLING SEQUENCE:
       Result = File_Open( FileID/Filename )

 INPUT ARGUMENTS:
       Specify one of:

         FileID:     The logical unit number of the file.
                     UNITS:      N/A
                     TYPE:       INTEGER
                     DIMENSION:  Scalar
                     ATTRIBUTES: INTENT( IN )
       or

         Filename:   The name of the file.
                     UNITS:      N/A
                     TYPE:       CHARACTER( * )
                     DIMENSION:  Scalar
                     ATTRIBUTES: INTENT( IN )

 OUTPUT ARGUMENTS:
       None.

 FUNCTION RESULT:
       Result:       The return value is a logical result.
                     If .TRUE.  the file is open.
                        .FALSE. the file is not open
                     UNITS:      N/A
                     TYPE:       LOGICAL
                     DIMENSION:  Scalar

 CALLS:
       None.

 SIDE EFFECTS:
       None.

 RESTRICTIONS:
       It is assumed the file unit or name exists.

(See File_Utility.f90)