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HP OpenVMS Systems Documentation

HP OpenVMS DCL Dictionary

F$TYPE

Returns the data type of a symbol. The string INTEGER is returned if the symbol is equated to an integer, or if the symbol is equated to a string whose characters form a valid integer.
The string STRING is returned if the symbol is equated to a character string whose characters do not form a valid integer.
If the symbol is undefined, a null string ("") is returned.

Format

F$TYPE (symbol-name)

Return Value

The string INTEGER is returned if the symbol is equated to an integer, or if the symbol is equated to a string whose characters form a valid integer.

If the symbol has been produced by a call to the F$CONTEXT function with a context type of PROCESS or by a call to the F$PID function, the string returned is PROCESS_CONTEXT. A symbol retains this type until F$CONTEXT is called with the symbol and the CANCEL keyword, or until a null string ("") is returned by a call to F$PID.

Similarly, the return value is the string CLUSTER_SYSTEM_CONTEXT for symbols created by the F$CSID function.

If the symbol is a context symbol, then the return value will be one of the types shown in Table DCLI-12.

**Table DCLI-12 Context Symbol Types**
Symbol Type	Lexical Creating Symbol
PROCESS_CONTEXT	F$PID or F$CONTEXT (with PROCESS context type)
CLUSTER_SYSTEM_CONTEXT	F$CSID

The string STRING is returned if the symbol is equated to a character string whose characters do not form a valid integer or whose type is not a context.

If the symbol is undefined, a null string is returned.

Argument

symbol-name
Specifies the name of the symbol to be evaluated.

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.

$ 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.

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