G.2 Numeric Performance Requirements

Implementations shall provide a user-selectable mode in which the accuracy and other numeric performance requirements detailed in the following subclauses are observed. This mode, referred to as the strict mode, may or may not be the default mode; it directly affects the results of the predefined arithmetic operations of real types and the results of the subprograms in children of the Numerics package, and indirectly affects the operations in other language defined packages. Implementations shall also provide the opposing mode, which is known as the relaxed mode. 

Either mode may be the default mode. 

The two modes need not actually be different.