round, i64round

`round`, `i64round`

Library: fbudf

Added in: 1.0 (Win), 1.5 (Linux)

Changed in: 1.5, 2.1.3

Better alternative: Internal function ROUND()

Description: These functions return the whole number that is nearest to their (scaled numeric/decimal) argument. They do not work with floats or doubles.

Result type: INTEGER / NUMERIC(18,4)

Syntax:

round    (number)
i64round (bignumber)

Caution

Halves are always rounded upward, i.e. away from zero for positive numbers and toward zero for negative numbers. For instance, 3.5 is rounded to 4, but -3.5 is rounded to -3. The internal function ROUND, available since Firebird 2.1, rounds all halves away from zero.

Bug alert

In versions 2.1, 2.1.1 and 2.1.2, these functions are broken for negative numbers:

Anything between 0 and -0.6 (that's right: -0.6, not -0.5) is rounded to 0.
Anything between -0.6 and -1 is rounded to +1 (plus 1).
Anything between -1 and -1.6 is rounded to -1.
Anything between -1.6 and -2 is rounded to -2.
Etcetera.

Fixed in 2.1.3.

Declarations:

In Firebird 1.0.x, the entry point for both functions is round:
DECLARE EXTERNAL FUNCTION Round
   INT BY DESCRIPTOR, INT BY DESCRIPTOR
   RETURNS PARAMETER 2
   ENTRY_POINT 'round' MODULE_NAME 'fbudf'
DECLARE EXTERNAL FUNCTION i64Round
   NUMERIC(18,4) BY DESCRIPTOR, NUMERIC(18,4) BY DESCRIPTOR
   RETURNS PARAMETER 2
   ENTRY_POINT 'round' MODULE_NAME 'fbudf'
In Firebird 1.5, the entry point has been renamed to fbround:
DECLARE EXTERNAL FUNCTION Round
   INT BY DESCRIPTOR, INT BY DESCRIPTOR
   RETURNS PARAMETER 2
   ENTRY_POINT 'fbround' MODULE_NAME 'fbudf'
DECLARE EXTERNAL FUNCTION i64Round
   NUMERIC(18,4) BY DESCRIPTOR, NUMERIC(18,4) BY DESCRIPTOR
   RETURNS PARAMETER 2
   ENTRY_POINT 'fbround' MODULE_NAME 'fbudf'
If you move an existing database from Firebird 1.0.x to 1.5 or higher, drop any existing *round and *truncate declarations and declare them anew, using the updated entry point names. From Firebird 2.0 onward you can also perform this update with ALTER EXTERNAL FUNCTION.