scalb(3) [netbsd man page]

IEEE_TEST(3)						   BSD Library Functions Manual 					      IEEE_TEST(3)

NAME

     logb, logbf, logbl, scalb, scalbf, significand, significandf -- IEEE test functions

LIBRARY

     Math Library (libm, -lm)

SYNOPSIS

     #include <math.h>

     double
     logb(double x);

     float
     logbf(float x);

     long double
     logbl(long double x);

     double
     scalb(double x, double n);

     float
     scalbf(float x, float n);

     double
     significand(double x);

     float
     significandf(float x);

DESCRIPTION

     These functions allow users to test conformance to IEEE Std 754-1985.  Their use is not otherwise recommended.

     logb(x) returns x's exponent n, a signed integer converted to double-precision floating-point.  logb(+-infinity) = +infinity; logb(0) =
     -infinity with a division by zero exception.

     scalbn(x, n) returns x*(2**n) computed by exponent manipulation.

     significand(x) returns sig, where x := sig * 2**n with 1 <= sig < 2.  significand(x) is not defined when x is 0, +-infinity, or NaN.

SEE ALSO

     math(3)

STANDARDS

     IEEE Std 754-1985

BSD
								  August 3, 2011							       BSD

ILOGB(3)						   BSD Library Functions Manual 						  ILOGB(3)

NAME

     ilogb, ilogbf, ilogbl, logb, logbf, logbl -- extract exponent

LIBRARY

     Math Library (libm, -lm)

SYNOPSIS

     #include <math.h>

     int
     ilogb(double x);

     int
     ilogbf(float x);

     int
     ilogbl(long double x);

     double
     logb(double x);

     float
     logbf(float x);

     long double
     logbl(long double x);

DESCRIPTION

     ilogb(), ilogbf() and ilogbl() return x's exponent in integer format.  ilogb(+-infinity) returns INT_MAX, ilogb(+-NaN) returns FP_ILOGBNAN,
     and ilogb(0) returns FP_ILOGB0.

     logb(x), logbf(x), and logbl(x) return x's exponent in floating-point format with the same precision as x.  logb(+-infinity) returns +infin-
     ity, and logb(0) returns -infinity with a division by zero exception.

SEE ALSO

     frexp(3), ieee(3), math(3), scalbn(3)

STANDARDS

     The ilogb(), ilogbf(), ilogbl(), logb(), logbf(), and logbl() routines conform to ISO/IEC 9899:1999 (``ISO C99'').  The latter three imple-
     ment the logb function recommended by IEEE Std 754-1985.

HISTORY

     Function	First Appeared In
     logb()	4.3BSD
     ilogb()	FreeBSD 1.1.5
     ilogbf()	FreeBSD 2.0
     logbf()	FreeBSD 2.0
     ilogbl()	FreeBSD 5.4
     logbl()	FreeBSD 8.0

BSD
								 December 16, 2007							       BSD