Ada Programming/Attributes/'Copy Sign

function S'Copy_Sign (Value, Sign : T)
  return T

Description

S'Copy_Sign(X, Y) is an Ada attribute where S is any floating-point type, and X and Y are any instance of that type. This attribute represents the floating point value with the magnitude of X and the sign of Y.

If the resulting value is outside the base range of S, a Constraint_Error exception is raised.

Example

X : Float :=  1.5;
Y : Float := -1.0;
Z : Float :=  1.0;
 
pragma Assert (Float'Copy_Sign ( X, Y) = -1.5);   -- OK
pragma Assert (Float'Copy_Sign ( X, Z) =  1.5);   -- OK
pragma Assert (Float'Copy_Sign (-X, Z) =  1.5);   -- OK
pragma Assert (Float'Copy_Sign ( Y, Z) = -1.0);   -- Wrong

See also

Wikibook

• Ada Programming
• Ada Programming/Attributes

Ada Reference Manual

• A.5.3 Attributes of Floating Point Types (Annotated)
• Annex K Language-Defined Attributes (Annotated)