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HP OpenVMS Systems Documentation
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HP Fortran for OpenVMS
Language Reference Manual

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12.6.12 DISPOSE Specifier

The DISPOSE (or DISP) specifier indicates the status of the file after the unit is closed. It takes one of the following forms:


  • DISPOSE = dis
  • DISP = dis

dis

Is a scalar default character expression that evaluates to one of the following values:
' KEEP ' or ' SAVE ' Retains the file after the unit closes.
' DELETE ' Deletes the file after the unit closes.
' PRINT ' 1 Submits the file to the system line printer spooler and retains it.
' PRINT/DELETE ' 1 Submits the file to the system line printer spooler and then deletes it.
' SUBMIT ' Submits the file to the batch job queue and then retains it.
' SUBMIT/DELETE ' Submits the file to the batch job queue and then deletes it.
1Use only on sequential files.

A read-only file cannot be deleted.

The default is ' DELETE ' for scratch files; a scratch file cannot be saved, printed, or submitted. For all other files, the default is ' KEEP ' .

12.6.13 EXTENDSIZE Specifier

The EXTENDSIZE specifier indicates the number of blocks by which to extend a disk file (extent) when additional storage space is needed. It takes the following form:


  • EXTENDSIZE = es

es

Is a scalar numeric expression.

If you do not specify EXTENDSIZE or if you specify zero, the process or system default for the device is used.

For More Information:

On the relationship between the EXTENDSIZE specifier and the INITIALSIZE specifier, see Section 12.6.16.

12.6.14 FILE Specifier

The FILE specifier indicates the name of the file to be connected to the unit. It takes the following form:


  • FILE = name

name

Is a character or numeric expression.

The name can be any specification allowed by the operating system.

Any trailing blanks in the name are ignored.

If the following conditions occur:

  • FILE is omitted
  • The unit is not connected to a file
  • STATUS= ' SCRATCH ' is not specified

then HP Fortran generates a file name in the form FORnnn.DAT, where nnn is the logical unit number (with leading zeros, if necessary).

If the file name is stored in a numeric scalar or array, the name must consist of ASCII characters terminated by an ASCII null character (zero byte). However, if it is stored in a character scalar or array, it must not contain a zero byte.

For More Information:

  • On default file name conventions, see the HP Fortran for OpenVMS User Manual.
  • On allowable file specifications, see the appropriate manual in your system documentation set.

12.6.15 FORM Specifier

The FORM specifier indicates whether the file is being connected for formatted or unformatted data transfer. It takes the following form:


  • FORM = fm

fm

Is a scalar default character expression that evaluates to one of the following values:
' FORMATTED ' Indicates formatted data transfer
' UNFORMATTED ' Indicates unformatted data transfer

The default is ' FORMATTED ' for sequential access files, and ' UNFORMATTED ' for direct and keyed access files.

12.6.16 INITIALSIZE Specifier

The INITIALSIZE specifier indicates the number of blocks in the initial storage allocation (extent) for a disk file. This information is used by the EXTENDSIZE specifier, which indicates the number of blocks by which a disk file is extended each time more space is needed for a file. The INITIALSIZE specifier takes the following form:


  • INITIALSIZE = insz

insz

Is a scalar numeric expression.

If you do not specify INITIALSIZE or if you specify zero, no initial allocation is made. The system attempts to allocate contiguous space for INITIALSIZE, but noncontiguous space is allocated if there is not enough contiguous space available.

INITIALSIZE is effective only at the time the file is created. If EXTENDSIZE is specified when the file is created, the value specified is the default value used to allocate additional storage for the file.

If you specify EXTENDSIZE when you open an existing file, the value you specify supersedes any EXTENDSIZE value specified when the file was created, and remains in effect until you close the file. Unless specifically overridden, the default EXTENDSIZE value is in effect on subsequent openings of the file.

12.6.17 KEY Specifier

The KEY specifier defines the access keys for records in an indexed file. It takes the following form:


  • KEY = (kspec [,kspec]...)

kspec

Takes the following form:

  • e1:e2 [:dt[:dr]]

e1

Is the first byte position of the key.

e2

Is the last byte position of the key.

dt

Is the data type of the key: INTEGER or CHARACTER.

dr

Is the direction of the key: ASCENDING or DESCENDING.

The defaults are CHARACTER and ASCENDING.

The key starts at position e1 in a record and has a length of e2-e1+1 . The values of e1 and e2 must cause the following calculations to be true: 


1 .LE. (e1) .AND. (e1) .LE. (e2) .AND. (e2) .LE. record-length
1 .LE. (e2-e1+1) .AND. (e2-e1+1) .LE. 255

If the key type is INTEGER, the key length must be either 2 or 4.

Defining Primary and Alternate Keys

You must define at least one key in an indexed file. This is the primary key (the default key). It usually has a unique value for each record.

You can also define alternate keys. RMS allows up to 254 alternate keys.

If a file requires more keys than the OPEN statement limit, you must create the file using another language or the File Definition Language (FDL).

Specifying and Referencing Keys

You must use the KEY specifier when creating an indexed file. However, you do not have to respecify it when opening an existing file, because key attributes are permanent aspects of the file. These attributes include key definitions and reference numbers for subsequent I/O operations.

However, if you use the KEY specifier for an existing file, your specification must be identical to the established key attributes.

Subsequent I/O operations use a reference number, called the key-of-reference number, to identify a particular key. You do not specify this number; it is determined by the key's position in the specification list: the primary key is key-of-reference number 0; the first alternate key is key-of-reference number 1, and so forth.

For More Information:

On the FDL, see the OpenVMS Record Management Services Reference Manual.

12.6.18 MAXREC Specifier

The MAXREC specifier indicates the maximum number of records that can be transferred from or to a direct access file while the file is connected. It takes the following form:


  • MAXREC = mr

mr

Is a scalar numeric expression. If necessary, the value is converted to integer data type before use.

The default is the maximum allowed (2**32--1).

12.6.19 NAME Specifier

NAME is a nonstandard synonym for FILE (see Section 12.6.14).

12.6.20 NOSPANBLOCKS Specifier

The NOSPANBLOCKS specifier indicates that records are not to cross disk block boundaries. It takes the following form:


  • NOSPANBLOCKS

This specifier causes an error to occur if any record exceeds the size of a physical block.

12.6.21 ORGANIZATION Specifier

The ORGANIZATION specifier indicates the internal organization of the file. It takes the following form:


  • ORGANIZATION = org

org

Is a scalar default character expression that evaluates to one of the following values:
' SEQUENTIAL ' Indicates a sequential file.
' RELATIVE ' Indicates a relative file.
' INDEXED ' Indicates an indexed file.

The default is ' SEQUENTIAL ' . However, if you omit the ORGANIZATION specifier when you open an existing file, the organization already specified in that file is used. If you specify ORGANIZATION for an existing file, org must have the same value as that of the existing file.

12.6.22 PAD Specifier

The PAD specifier indicates whether a formatted input record is padded with blanks when an input list and format specification requires more data than the record contains.

The PAD specifier takes the following form:


  • PAD = pd

pd

Is a scalar default character expression that evaluates to one of the following values:
' YES ' Indicates the record will be padded with blanks when necessary.
' NO ' Indicates the record will not be padded with blanks. The input record must contain the data required by the input list and format specification.

The default is ' YES ' .

This behavior is different from FORTRAN 77, which never pads short records with blanks. For example, consider the following: 


READ (5,'(I5)') J

If you enter 123 followed by a carriage return, FORTRAN 77 turns the I5 into an I3 and J is assigned 123.

However, HP Fortran pads the 123 with 2 blanks unless you explicitly open the unit with PAD= ' NO ' .

You can override blank padding by explicitly specifying the BN edit descriptor.

The PAD specifier is ignored during output.

12.6.23 POSITION Specifier

The POSITION specifier indicates the position of a file connected for sequential access. It takes the following form:


  • POSITION = pos

pos

Is a scalar default character expression that evaluates to one of the following values:
' ASIS ' Indicates the file position is unchanged if the file exists and is already connected. The position is unspecified if the file exists but is not connected.
' REWIND ' Indicates the file is positioned at its initial point.
' APPEND ' Indicates the file is positioned at its terminal point (or before its end-of-file record, if any).

The default is ' ASIS ' .

A new file (whether specified as new explicitly or by default) is always positioned at its initial point.

For More Information:

On record position, advancement, and transfer, see the HP Fortran for OpenVMS User Manual.

12.6.24 READONLY Specifier

The READONLY specifier indicates only READ statements can refer to this connection. It takes the following form:


  • READONLY

READONLY is similar to specifying ACTION= ' READ ' , but READONLY prevents deletion of the file if it is closed with STATUS= ' DELETE ' in effect.

Default file access privileges are READWRITE, which can cause run-time I/O errors if the file protection does not permit write access.

The READONLY specifier has no effect on the protection specified for a file. Its main purpose is to allow a file to be read simultaneously by two or more programs. For example, use READONLY if you wish to open a file so you can read it, but you also want others to be able to read the same file while you have it open.

For More Information:

On file sharing, see the HP Fortran for OpenVMS User Manual.

12.6.25 RECL Specifier

The RECL specifier indicates the length of each record in a file connected for direct or keyed access, or the maximum length of a record in a file connected for sequential access.

The RECL specifier takes the following form:


  • RECL = rl

rl

Is a positive numeric expression indicating the length of records in the file. If necessary, the value is converted to integer data type before use.

If the file is connected for formatted data transfer, the value must be expressed in bytes (characters). Otherwise, the value is expressed in 4-byte units (longwords). If the file is connected for unformatted data transfer, the value can be expressed in bytes if compiler option /ASSUME=BYTERECL is specified.

The rl value is the length for record data only. It does not include space for control information, such as two segment control bytes (if present) or the bytes that RMS requires for maintaining record length and deleted record control information.

The length specified is interpreted depending on the type of records in the connected file, as follows:

  • For segmented records, RECL indicates the maximum length for any segment (not including the two segment control bytes).
  • For fixed-length records, RECL indicates the size of each record.
  • For variable-length or stream records, RECL specifies the size of the buffer that will be allocated to hold records read or written. Specifying RECL for stream records (STREAM, STREAM_CR or STREAM_LF) is required if the longest record length in the file exceeds the default RECL value.

Errors occur under the following conditions:

  • If your program attempts to write to an existing file a record that is longer than the logical record length
  • If you are opening an existing file that contains fixed-length records or has relative organization and you specify a value for RECL that is different from the actual length of the records in the file

Table 12-2 lists the maximum values that can be specified for rl for disk files that use the fixed-length record format:

Table 12-2 Maximum Record Lengths (RECL)
  Record I/O Statement Format
File Organization Formatted (bytes) Unformatted (longwords)
Sequential 32767 8191
Relative 32255 8063
Indexed 32224 8056

For other record formats and device types, the record size limit may be less, as described in the OpenVMS Record Management Services Reference Manual.

You must specify RECL when opening new files (STATUS= ' NEW ' , ' UNKNOWN ' , or ' SCRATCH ' ) and one or more of the following conditions exists:

  • The file is connected for direct access (ACCESS= ' DIRECT ' ).
  • The record format is fixed length (RECORDTYPE= ' FIXED ' ).
  • The file organization is relative or indexed (ORGANIZATION= ' RELATIVE ' or ' INDEXED ' ).

The default value depends on the setting of the RECORDTYPE specifier, as shown in Table 12-3.

Table 12-3 Default Record Lengths (RECL)
RECORDTYPE RECL value
' FIXED ' None; value must be explicitly specified
All other types 133 bytes (for formatted records)
511 longwords (for unformatted records)

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