Converts any data type into the LOGICAL data type.
Syntax
LOGICAL ( expression [ , char-expression-format ] )
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-
expression
- An expression in the data type that you want to
convert to logical.
-
char-expression-format
- A character expression that evaluates to a valid logical format,
such as "si/no", or "da/nyet". This
argument is ignored unless expression is of CHARACTER
type. Also, this argument is only needed if expression evaluates
to something other than the usual TRUE or FALSE, or YES or NO values.
Example
The
following code fragment illustrates the Logical function:
DEFINE VARIABLE mychar AS CHARACTER NO-UNDO.
DEFINE VARIABLE v-log AS LOGICAL NO-UNDO.
mychar = "si".
v-log = LOGICAL(mychar, "si/no")
/* v-log is TRUE */
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Notes
- If
the value of expression is the Unknown value (?),
the LOGICAL function returns the Unknown value (?).
- If expression is of type DECIMAL, INTEGER, INT64,
DATE, DATETIME, DATTIME-TZ, or HANDLE, the function returns TRUE
if the value of expression is nonzero. If the
value of expression is 0, it returns FALSE. The second
argument is ignored if present.
- If expression is of type LONGCHAR or CHARACTER,
it returns TRUE or FALSE depending on the value in the expression
and the format used. Whether or not char-expression-format is
given, the case-insensitive values TRUE, FALSE, YES, NO, abbreviated
to 1 character, are always accepted. For example, a "Y" is interpreted
as TRUE.
- If char-expression-format is given, it is
validated. If it is not valid, an error message appears and the Unknown value (?) is
returned. Otherwise, the format is used to interpret the character
string if it is not one of the following: TRUE, FALSE, YES, or NO.
For example, LOGICAL ("si", "si/no"
) returns TRUE.
- Data types such as RAW, MEMPTR, LVARBINARY, and so on return
the Unknown value (?), but this is not considered an error.
