42.2 – Argument
symbol-name
Specifies the name of the symbol to be evaluated.
42.3 – Examples
1.$ NUM = "52"
$ TYPE = F$TYPE(NUM)
$ SHOW SYMBOL TYPE
TYPE = "INTEGER"
This example uses the F$TYPE function to determine the data
type of the symbol NUM. NUM is equated to the character
string "52". Because the characters in the string form a valid
integer, the F$TYPE function returns the string INTEGER.
2.$ NUM = 52
$ TYPE = F$TYPE(NUM)
$ SHOW SYMBOL TYPE
TYPE = "INTEGER"
In this example, the symbol NUM is equated to the integer 52.
The F$TYPE function shows that the symbol has an integer data
type.
3.$ CHAR = "FIVE"
$ TYPE = F$TYPE(CHAR)
$ SHOW SYMBOL TYPE
TYPE = "STRING"
In this example, the symbol CHAR is equated to the character
string FIVE. Because the characters in this string do not form
a valid integer, the F$TYPE function shows that the symbol has
a string value.
4.$ x = F$CONTEXT("PROCESS",CTX,"USERNAME","SMITH")
$ TYPE = F$TYPE(CTX)
$ SHOW SYMBOL TYPE
TYPE = "PROCESS_CONTEXT"
$ x = F$CONTEXT("PROCESS",CTX,"CANCEL")
$ TYPE = F$TYPE(CTX)
$ SHOW SYMBOL TYPE
TYPE = ""
In this example, the F$TYPE function returns the string
PROCESS_CONTEXT because the symbol has been produced by a call
to the F$CONTEXT function with a context type of PROCESS. The
symbol returns this type until F$CONTEXT is called with the
symbol and the selection-item argument value CANCEL.
43 – F$UNIQUE
Valid on Alpha and Integrity server systems only.
Generates a string that is suitable to be a file name and is
guaranteed to be unique across the cluster. Unique file names can
be useful when creating temporary files. The string returned
is alphanumeric and may be used as a file name, logical name,
or DCL symbol name or value with no reserved character issues.
The F$UNIQUE function has no arguments, but must be followed by a
blank pair of parentheses.
Format
F$UNIQUE()
43.1 – Return Value
A character string containing the unique string.
43.2 – Examples
1.$ WRITE SYS$OUTPUT F$UNIQUE()
414853555241159711D7DF797CCF573F
$
$ WRITE SYS$OUTPUT F$UNIQUE()
414853555241509811D7DF797E3F2777
$
This example shows how a unique string is returned on
subsequent WRITE commands.
2.$ OPEN/WRITE TEMP_FILE 'F$UNIQUE()
$ DIRECTORY
Directory WORK1:[TEST]
594B53554C421C9C11D75463D61F58B7.DAT;1
Total of 1 file.
$
$ CLOSE/DISPOSITION=DELETE TEMP_FILE
$ DIRECTORY
%DIRECT-W-NOFILES, no files found
$
The first command creates a temporary file and gives it a
unique name, which is displayed by the subsequent DIRECTORY
command. After the file is later closed and deleted, it no
longer shows up in the directory.
44 – F$USER
Returns the current user identification code (UIC) in named
format as a character string. The F$USER function has no
arguments, but must be followed by parentheses.
Format
F$USER()
44.1 – Return Value
A character string containing the current UIC, including brackets
([ ]). The UIC is returned in the format [group-identifier,
member-identifier].
44.2 – Example
$ UIC = F$USER()
$ SHOW SYMBOL UIC
UIC = "[GROUP6,JENNIFER]"
In this example, the F$USER function returns the current user
identification code and assigns it to the symbol UIC.
45 – F$VERIFY
Returns an integer value indicating whether the procedure
verification setting is currently on or off. If used with
arguments, the F$VERIFY function can turn the procedure and image
verification settings on or off. You must include the parentheses
after the F$VERIFY function whether or not you specify arguments.
Format
F$VERIFY([procedure-value] [,image-value])
45.1 – Return Value
The integer 0 if the procedure verification setting is off, or
the integer 1 if the procedure verification setting is on.
45.2 – Arguments
procedure-value
Specifies an integer expression with a value of 1 to turn
procedure verification on, or a value of 0 to turn procedure
verification off.
When procedure verification is on, each DCL command line in the
command procedure is displayed on the output device. Procedure
verification allows you to verify that each command is executing
correctly.
If you use the procedure-value argument, the function first
returns the current procedure verification setting. Then the
command interpreter turns the procedure verification on or off,
as specified by the argument.
image-value
Specifies an integer expression with a value of 1 to turn image
verification on, or a value of 0 to turn image verification off.
When image verification is on, data lines in the command
procedure are displayed on the output device.
45.3 – Examples
1.$ SAVE_PROC_VERIFY = F$ENVIRONMENT("VERIFY_PROCEDURE")
$ SAVE_IMAGE_VERIFY = F$ENVIRONMENT("VERIFY_IMAGE")
$ SET NOVERIFY
.
.
.
$ TEMP = F$VERIFY(SAVE_PROC_VERIFY, SAVE_IMAGE_VERIFY)
This example shows an excerpt from a command procedure. The
first assignment statement assigns the current procedure
verification setting to the symbol SAVE_PROC_VERIFY. The second
assignment statement assigns the current image verification
setting to the symbol SAVE_IMAGE_VERIFY.
Then, the SET NOVERIFY command disables procedure and image
verification. Later, the F$VERIFY function resets the
verification settings, using the original values (equated to
the symbols SAVE_PROC_VERIFY and SAVE_IMAGE_VERIFY). The symbol
TEMP contains the procedure verification before it is changed
with the F$VERIFY function. (In this example, the value of TEMP
is not used.)
2.$ VERIFY = F$VERIFY(0)
.
.
.
$ IF VERIFY .EQ. 1 THEN SET VERIFY
This example shows an excerpt from a command procedure that
uses the F$VERIFY function to save the current procedure
verification setting and to turn both procedure and image
verification off. At the end of the command procedure, if
procedure verification was originally on, both the procedure
and image verification are turned on.