SGN

• Source: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgSgn
• Last revised: 2024-01-29

---

Returns the sign part of a number

Syntax

` declare function Sgn ( byval number as numtype ) as numtype

`

Usage

` result = Sgn( number )

`

Parameters

number

the number to find the sign of

numtype

a numeric type

Return Value

Returns the sign part of number.

• If number is greater than zero, then Sgn returns 1.
• If number is equal to zero, then Sgn returns 0.
• If number is less than zero, then Sgn returns -1.

Description

The required number argument can be any valid numeric expression.

Unsigned numbers of size greater than or equal to SizeOf(Any Ptr) will be treated as if they were signed, i.e. if the highest bit is set the number will be treated as negative, and -1 will be returned.

Note:

The return type of Sgn depends on the type of the passed argument (variable or constant, its data type), and of the used backend (gas, gas64, gcc 32-bit, gcc 64-bit):

• Sgn return type for a variable passed as argument:

Argument	gas (32-bit)	gas64 (64-bit)	gcc 32-bit (*)	gcc 64-bit (*)
[U]BYTE variable	INTEGER	INTEGER	LONG	LONG
[U]SHORT variable	INTEGER	INTEGER	LONG	LONG
[U]LONG variable	INTEGER	INTEGER	LONG	LONG
[U]INTEGER variable	INTEGER	INTEGER	LONG	LONG
[U]LONGINT variable	LONGINT	INTEGER	LONG	LONG
SINGLE variable	SINGLE	LONG	LONG	LONG
DOUBLE variable	DOUBLE	LONG	LONG	LONG

• Sgn return type for a constant passed as argument:

Argument	gas (32-bit)	gas64 (64-bit)	gcc 32-bit (*)	gcc 64-bit (*)
[U]BYTE constant	INTEGER	INTEGER	INTEGER	INTEGER
[U]SHORT constant	INTEGER	INTEGER	INTEGER	INTEGER
[U]LONG constant	INTEGER	INTEGER	INTEGER	INTEGER
[U]INTEGER constant	INTEGER	INTEGER	INTEGER	INTEGER
[U]LONGINT constant	LONGINT	INTEGER	LONGINT	INTEGER
SINGLE constant	SINGLE	SINGLE	SINGLE	SINGLE
DOUBLE constant	DOUBLE	DOUBLE	DOUBLE	DOUBLE

(*): applicable also for clang and llvm

The Sgn unary operator can be overloaded with user defined types.

Examples

start GeSHi

Dim N As Integer = 0

Print Sgn ( -1.87 )
Print Sgn ( 0 )
Print Sgn ( 42.658 )
Print Sgn ( N )

end GeSHi

The output would look like:

-1
0
1
0

Dialect Differences

• In the -lang qb dialect, this operator cannot be overloaded.

Differences from QB

• None

See also

• Abs
• Operator

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