DIRECT

Define Single-Keyed Access File

This directive is used to create a new, single-keyed data file in a logical disk directory.

Syntax

DIRECT file-name, key-size, num-records, record-size,
                  disk-num, sector-num [,ERR=line-ref|,ERC=error-code]

file-name: is any string of 8 characters or fewer used to name this file.
key-size: is an integer in the range of 1 to 144 indicating the size, in bytes, of this file's key.
num-records: is an integer in the range of 0 to 16,777,215 indicating the maximum number of records to be contained in this file.
record-size: is an integer in the range of 4 to 32767 indicating the number of bytes in each record in this file.
disk-num: specifies the logical disk directory that contains this file. Valid values are 0 through 35.
sector-num: is required but is normally the number 0 (zero) since each operating system allocates where the file is stored. A value of -9 (minus 9) will create the file Encrypted. If Encrypted the first 3 bytes of the file’s FID will be “ENC”.
line-ref: is the program line number or label to branch to if this directive produces an error.
error-code: is a programmer-defined error code. Valid values are positive or negative whole numbers.

Remarks

If any integer range is exceeded, an ERR=41 results.

If a file-name of more than eight characters (operating system-specific) is specified, an ERR=10 results.

All valid values for sector-num are treated as 0, but syntax requires sector-num to be specified.

File-name must be unique in the execution environment. An attempt to define a file having the same name as another file that is already defined on an available logical disk directory results in an ERR=12.

The file-name can contain any ASCII characters, unprintable as well as printable. Avoid using characters which have special meaning in different operating system environments, for example, “ * “ in UNIX and Microsoft Windows, “ / “ in UNIX, “ # “ and “ \ “ in Microsoft Windows, and so on.

To avoid confusion do not use device or task names as file-names. For example, do not use T0 - T9, TA - TZ, Ta - Tz, D0 - Dz, LP, P0 - Pz, G0 - Gz, C0 - Cz. In general, most device and task names use two-character names. The simplest approach is to not use two-character file-names.

Starting with release level 8.3.1, you can define num-records as 0. This dynamic file type has no EOF (end of file) restrictions, so the necessity for file expansion is removed. The file can contain more than 2 billion records and 140 trillion characters. The minimum record size for this type of DIRECT file is 6 characters.

Examples

DIRECT "SEAL", 10, 57, 26, 2, 0

creates a DIRECT file named “SEAL” with the following parameters: key length is 10 bytes, 57 records with a length of 26 bytes each, and a location on logical disk 2 starting at a sector allocated by the operating system.

DIRECT A$, A, B, C, D, E, ERR=7999

If A$=“SEAL”, A=10, B=57, C=26, D=2, and E=0 has the same effect as the first example and branches to statement 7999 if this directive produced an error.

DIRECT

Syntax

Remarks

Examples

See also