PGI Fortran Reference manual - The Portland Group

Fortran Intrinsics6.29. IEEE_FEATURESThe ieee_features intrinsic module supports specification of essential IEEE features. Itprovides access to one derived type and a collection of named constants of this type, each ofwhich corresponds to an IEEE feature. The named constants affect the manner in which code iscompiled in the scoping units.6.29.1. IEEE_FEATURES Derived TypeThe ieee_features intrinsic module provides access to the derived type:ieee_features_type. This type identifies a particular feature. It may only take values thatare those of named constants defined in the module.While permitted, there is no purpose in declaring data of type ieee_features_type. Thecomponents of this type are private, no operation is defined for it, and only intrinsic assignment isavailable for it.6.29.2. IEEE_FEATURES Named ConstantsTable 29 lists a complete set of named constants available for the ieee_features intrinsicmodule and provides the effect of their accessibility:Table 29 IEEE_FEATURES Named ConstantsThis named constant... Requires the scoping unit to support ...ieee_datatypeieee_denormalieee_divideieee_haltingieee_inexact_flagieee_infieee_invalid_flagieee_nanieee_roundingieee_sqrtieee_underflow_flagieee_ARITHMETIC for at least one kind of real.Denormalized numbers for at least one kind of real.IEEE divide for at least one kind of real.Control of halting for each flag supported.Inexact exception for at least one kind of real.Infinity and -infinity for at least one kind of real.Invalid exception for at least one kind of real.NaNs for at least one kind of real.Control of the rounding mode for all four rounding modes on at least one kind of real.IEEE square root for at least one kind of real.Underflow exception for at least one kind of real.Some features may slow execution on some processorts. Therefore, if ieee_exceptions isaccessed but ieee_features is not, the processor can support a selected subset of the features.PGI Fortran Reference Guide 119