float man page on OpenIndiana

Man page or keyword search:  
man Server   20441 pages
apropos Keyword Search (all sections)
Output format
OpenIndiana logo
[printable version]

float.h(3HEAD)			    Headers			float.h(3HEAD)

NAME
       float.h, float - floating types

SYNOPSIS
       #include <float.h>

DESCRIPTION
       The  characteristics  of floating types are defined in terms of a model
       that describes a representation of floating-point  numbers  and	values
       that  provide  information  about  an  implementation's	floating-point
       arithmetic.

       The following parameters are used to define the model for  each	float‐
       ing-point type:

       s     sign (±1)

       b     base or radix of exponent representation (an integer >1)

       e     exponent  (an  integer  between  a	 minimum  e(min) and a maximum
	     e(max))

       p     precision (the number of base-b digits in the significand)

       f(k)  non-negative integers less than b (the significand digits)

       In addition to  normalized  floating-point  numbers  (f(1)>0  if	 x≠0),
       floating	 types	might be able to contain other kinds of floating-point
       numbers, such  as  subnormal  floating-point  numbers  (x≠0,  e=e(min),
       f(1)=0)	 and   unnormalized  floating-point  numbers  (x≠0,  e=e(min),
       f(1)=0), and values  that  are  not  floating-point  numbers,  such  as
       infinities  and	NaNs.  A NaN is an encoding signifying Not-a-Number. A
       quiet NaN propagates through almost every arithmetic operation  without
       raising	a floating-point exception; a signaling NaN generally raises a
       floating-point exception when occurring as an arithmetic operand.

       The accuracy  of	 the  library  functions  in  math.h(3HEAD)  and  com‐
       plex.h(3HEAD)  that  return  floating-point  results  is defined on the
       libm(3LIB) manual page.

       All integer values in the <float.h> header, except FLT_ROUNDS, are con‐
       stant expressions suitable for use in #if preprocessing directives; all
       floating values	are  constant  expressions.  All  except  DECIMAL_DIG,
       FLT_EVAL_METHOD,	 FLT_RADIX, and FLT_ROUNDS have separate names for all
       three floating-point types. The floating-point model representation  is
       provided for all values except FLT_EVAL_METHOD and FLT_ROUNDS.

       The  rounding  mode for floating-point addition is characterized by the
       value of FLT_ROUNDS:

       -1    Indeterminable.

       0     Toward zero.

       1     To nearest.

       2     Toward positive infinity.

       3     Toward negative infinity.

       The values of operations with floating operands and values  subject  to
       the  usual  arithmetic conversions and of floating constants are evalu‐
       ated to a format whose  range  and  precision  might  be	 greater  than
       required by the type. The use of evaluation formats is characterized by
       the architecture-dependent value of FLT_EVAL_METHOD:

       -1    Indeterminable.

       0     Evaluate all operations and constants just to the range and  pre‐
	     cision of the type.

       1     Evaluate operations and constants of type float and double to the
	     range and precision of the	 double	 type;	evaluate  long	double
	     operations	 and  constants to the range and precision of the long
	     double type.

       2     Evaluate all operations and constants to the range and  precision
	     of the long double type.

       The values given in the following list are defined as constants.

	   o	  Radix of exponent representation, b.

		    FLT_RADIX

	   o	  Number  of  base-FLT_RADIX digits in the floating-point sig‐
		  nificand, p.

		    FLT_MANT_DIG
		    DBL_MANT_DIG
		    LDBL_MANT_DIG

	   o	  Number of decimal digits, n, such  that  any	floating-point
		  number  in  the  widest  supported floating type with p(max)
		  radix b digits can be rounded	 to  a	floating-point	number
		  with	n  decimal digits and back again without change to the
		  value.

		    DECIMAL_DIG

	   o	  Number of decimal digits, q, such  that  any	floating-point
		  number with q decimal digits can be rounded into a floating-
		  point number with p radix b digits and  back	again  without
		  change to the q decimal digits.

		    FLT_DIG
		    DBL_DIG
		    LDBL_DIG

	   o	  Minimum  negative integer such that FLT_RADIX raised to that
		  power minus 1 is a normalized floating-point number, e(min).

		    FLT_MIN_EXP
		    DBL_MIN_EXP
		    LDBL_MIN_EXP

	   o	  Minimum negative integer such that 10 raised to  that	 power
		  is in the range of normalized floating-point numbers.

		    FLT_MIN_10_EXP
		    DBL_MIN_10_EXP
		    LDBL_MIN_10_EXP

	   o	  Maximum  integer  such  that	FLT_RADIX raised to that power
		  minus 1 is a	representable  finite  floating-point  number,
		  e(max).

		    FLT_MAX_EXP
		    DBL_MAX_EXP
		    LDBL_MAX_EXP

	   o	  Maximum  integer such that 10 raised to that power is in the
		  range of representable finite floating-point numbers.

		    FLT_MAX_10_EXP
		    DBL_MAX_10_EXP
		    LDBL_MAX_10_EXP

       The values given in the following list are defined as constant  expres‐
       sions with values that are greater than or equal to those shown:

	   o	  Maximum representable finite floating-point number.

		    FLT_MAX
		    DBL_MAX
		    LDBL_MAX

       The  values given in the following list are defined as constant expres‐
       sions with implementation-defined (positive) values that are less  than
       or equal to those shown:

	   o	  The  difference between 1 and the least value greater than 1
		  that is representable in the given floating-point type,  b^1
		  - p.

		    FLT_EPSILON
		    DBL_EPSILON
		    LDBL_EPSILON

	   o	  Minimum    normalized	   positive   floating-point   number,
		  b^e(min)^-1.

		    FLT_MIN
		    DBL_MIN
		    LDBL_MIN

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       ┌─────────────────────────────┬─────────────────────────────┐
       │      ATTRIBUTE TYPE	     │	    ATTRIBUTE VALUE	   │
       ├─────────────────────────────┼─────────────────────────────┤
       │Interface Stability	     │Committed			   │
       ├─────────────────────────────┼─────────────────────────────┤
       │Standard		     │See standards(5).		   │
       └─────────────────────────────┴─────────────────────────────┘

SEE ALSO
       complex.h(3HEAD), math.h(3HEAD), attributes(5), standards(5)

SunOS 5.11			  17 Dec 2003			float.h(3HEAD)
[top]

List of man pages available for OpenIndiana

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net