28.2 Floating-Point Type Specifications

The standard library header file float.h defines a number of constants that describe the platform’s implementation of floating-point types float, double and long double. They include:

FLT_MIN

DBL_MIN

LDBL_MIN

Defines the minimum normalized positive floating-point values that can be represented with the type.

FLT_HAS_SUBNORM

DBL_HAS_SUBNORM

LDBL_HAS_SUBNORM

Defines if the floating-point type supports subnormal (or “denormalized”) numbers or not (see subnormal numbers).

FLT_TRUE_MIN

DBL_TRUE_MIN

LDBL_TRUE_MIN

Defines the minimum positive values (including subnormal values) that can be represented with the type.

FLT_MAX

DBL_MAX

LDBL_MAX

Defines the largest values that can be represented with the type.

FLT_DECIMAL_DIG

DBL_DECIMAL_DIG

LDBL_DECIMAL_DIG

Defines the number of decimal digits n such that any floating-point number that can be represented in the type can be rounded to a floating-point number with n decimal digits, and back again, without losing any precision of the value.