Open - IBM 5100 Basic Reference Manual

OPEN file ref/dev-address' [,file-numl [,{ 'user ID'll {IN }
char-var
f.J'
OUT
86
OPEN
The OPEN statement allows you to:
• Identify an attached device with a file reference code.
• Allocate space for the file.
• Specify the file number.
• Specify the identification to be used with the file.
• Specify the file usage (input or output).
The syntax of the OPEN statement is as shown:
. . [ {'user
10')'1
{I N }
OPEN file ref ,'dev-address' [,flle-numl , char-var
fJ'
OUT
where:
file ref is FLO to FL9 to specify the logical file to be associated with the physical
file identified by the remaining entries in the OPEN statement. This file specifi-
cation can also be referenced in GET, PUT, RESET, CLOSE, PRINT, PRINT
USING, MAT PRINT, MAT PUT, MAT GET, and MAT PRINT USING
statements.
'de v-address'
is the address of the device referenced by the file reference code.
Valid addresses are: 'E80' for the built-in tape unit, 'E40' for the auxiliary tape
unit, and '500' for the printer.
file-num
is a constant or numeric variable. The value of the file number is then
used to access the corresponding file on the device specified. Decimal values for
variables are truncated to an integer. See
Negative File Numbers.
char-var is a character variable or character constant enclosed in single quotation
marks. The first 17 characters provide the identification field in the header
record of a file being opened for output. If you open a file for input, and specify
a character variable for identification, the user
10
from the file is placed in the
character variable when OPEN is executed.
IN or OUT indicates whether the file is to be used for input (IN) or output (OUT).
A sample OPEN statement is as shown:
OPEN FL1, 'E80', 3, IN
In this example, file reference code F L 1 will be assigned to reference file 3 on the
built-in tape unit for input.
,/