[Cfp-interest 2748] macros like DBL_MAX and FLT_EVAL_METHOD

[Vincent Lefevre]

The N3096 5.2.4.2.2p29 example says:

  The following describes floating-point representations that also
  meet the requirements for single-precision and double-precision
  numbers in IEC 60559,29) and the appropriate values in a <float.h>
  header for types float and double:
[...]
  DBL_MAX  1.7976931348623157E+308 // decimal constant

But p19 says for FLT_EVAL_METHOD = 2: "evaluate all operations and
constants to the range and precision of the long double type."

Note the "and constants". So this seems wrong if FLT_EVAL_METHOD = 2.

And even

  ((double) 1.7976931348623157E+308)

may not be correct, since if the FP_CONTRACT pragma is ON,
(long double) DBL_MAX might not give the expected value.

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Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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