21 Language support library [language.support]

21.3 Implementation properties [support.limits]

21.3.3 Floating-point type properties [fp.style] 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