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3.5 Environmental Inquiry

There are nine important model-related values that are fixed for and characteristic of a given real kind; these values constitute a sort of ``fingerprint" for the kind and are useful in various computational contexts. The environmental inquiry intrinsic functions allow the programmer to access these values at any time, in (a) numerical expressions in declaration of data objects and(b) any computation. Each of these environmental intrinsics takes a single argument, which may be a constant, scalar variable, or array variable. If it is a variable, its value need not be defined because only the type kind of the argument is used by these functions, not the value of the argument. These nine characteristic values and related environmental intrinsic functions shown in Table 2:

Table 2: Environmental Intrinsic Functions.

Of these nine values, HUGE, TINY, and EPSILON are especially useful in writing robust portable numerical software, though in specialized contexts the others are tantamount to indispensable.