Documentation/How Tos/Calc: ISLOGICAL function
From Apache OpenOffice Wiki
Tests if a cell contains a logical value, TRUE or FALSE.
- Returns TRUE if value is either TRUE or FALSE, and FALSE otherwise.
- where D5 contains FALSE, returns TRUE, because D5 contains a logical value.
- returns FALSE, because 123 is a number, not a logical value.
- A logical value in Calc is simply a number with a boolean format, not a separate type as in Excel. Some resulting incompatibilities are discussed in Issue 84266.