Characteristics of floatingpoint types
This header describes the characteristics of floating types for the specific system and compiler implemetation used.
A floatingpoint number is composed of four elements:
 a sign: either negative or nonnegative
 a base (or radix): which expresses the amount of quantities that can be represented with a single digit (2 for binary, 10 for decimal, 16 for hexadecimal, and so on...)
 a significand (or mantissa): which is a series of digits of the abovementioned base. The number of digits in this series is what is known as precision.
 an exponent (also knon as characteristic, or scale): which represents the offset of the significand, which affects the value in the following way:
value of floatingpoint = significand x base^{exponent}, with its corresponding sign.
The following panel shows the name of the different values defined in this header and their minimal magnitudes (positive numbers may be greater in value, and negative number may be less in value). Any particular implementation may have characteristics with greater magnitudes than those shown here:
*Except for FLT_RADIX, names beginning with FLT apply to the float type, those with DBL to double and those with LDBL to long double.
name  min.  stands for  expresses 
FLT_RADIX  2  RADIX  Base for all floatingpoint types (float, double and long double). 
FLT_MANT_DIG
DBL_MANT_DIG
LDBL_MANT_DIG   MANTissa DIGits  Precission of significand, i.e. the number of digits that conform the significand. 
FLT_DIG
DBL_DIG
LDBL_DIG  6
10
10  DIGits  Number of decimal digits that can be rounded into a floatingpoint and back without change in the number of decimal digits. 
FLT_MIN_EXP
DBL_MIN_EXP
LDBL_MIN_EXP   MINimum EXPonent  Minimum negative integer value for the exponent that generates a normalized floatingpoint number. 
FLT_MIN_10_EXP
DBL_MIN_10_EXP
LDBL_MIN_10_EXP  37
37
37  MINimum base10 EXPonent  Minimum negative integer value for the exponent of a base10 expression that would generate a normalized floatingpoint number. 
FLT_MAX_EXP
DBL_MAX_EXP
LDBL_MAX_EXP   MAXimum EXPonent  Maximum integer value for the exponent that generates a normalized floatingpoint number. 
FLT_MAX_10_EXP
DBL_MAX_10_EXP
LDBL_MAX_10_EXP  37
37
37  MAXimum base10 EXPonent  Maximum integer value for the exponent of a base10 expression that would generate a normalized floatingpoint number. 
FLT_MAX
DBL_MAX
LDBL_MAX  1E+37
1E+37
1E+37  MAXimum  Maximum finite representable floatingpoint number. 
FLT_EPSILON
DBL_EPSILON
LDBL_EPSILON  1E5
1E9
1E9  EPSILON  Difference between 1 and the least value greater than 1 that is representable. 
FLT_MIN
DBL_MIN
LDBL_MIN  1E37
1E37
1E37  MINimum  Minimum representable floatingpoint number. 
See also
