17 Language support library [language.support]

17.3 Implementation properties [support.limits]

17.3.4 Floating-point type properties [fp.style]

17.3.4.2 Type float_­denorm_­style [denorm.style]

namespace std {
  enum float_denorm_style {
    denorm_indeterminate = -1,
    denorm_absent = 0,
    denorm_present = 1
  };
}
The presence or absence of subnormal numbers (variable number of exponent bits) is characterized by the values:
  • denorm_­indeterminate if it cannot be determined whether or not the type allows subnormal values
  • denorm_­absent if the type does not allow subnormal values
  • denorm_­present if the type does allow subnormal values