scalbf(3m) [sunos man page]

scalb(3M)						  Mathematical Library Functions						 scalb(3M)

NAME

       scalb, scalbf, scalbl - load exponent of a radix-independent floating-point number

SYNOPSIS

       cc [ flag... ] file... -lm [ library... ]
       #include <math.h>

       double scalb(double x, double n);

       float scalbf(float x, float n);

       long double scalbl(long double x, long double n);

DESCRIPTION

       These  functions  compute  x * r**n, where r is the radix of the machine's floating point arithmetic. When r is 2, scalb() is equivalent to
       ldexp(3M). The value of r is FLT_RADIX which is defined in <float.h>.

RETURN VALUES

       Upon successful completion, the scalb() function returns x * r**n.

       If x or n is NaN, a NaN is returned.

       If n is 0, x is returned.

       If x is +-Inf and n is not -Inf, x is returned.

       If x is +-0 and n is not +Inf, x is returned.

       If x is +-0 and n is +Inf, a domain error occurs and a NaN is returned.

       If x is +-Inf and n is -Inf, a domain error occurs and a NaN is returned.

       If the result would cause an overflow, a range error occurs and +-HUGE_VAL (according to the sign of x) is returned.

       For exceptional cases, matherr(3M) tabulates the values to be returned by scalb() as specified by SVID3 and XPG3. See standards(5).

ERRORS

       These functions will fail if:

       Domain Error    If x is 0 and n is +Inf, or x is Inf and n is -Inf.

		       If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the  invalid  floating-point  exception	is
		       raised.

       Range Error     The result would overflow.

		       If  the	integer  expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception is
		       raised.

USAGE

       An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before  calling	these  functions.  On  return,	if
       fetestexcept(FE_INVALID	|  FE_DIVBYZERO  |  FE_OVERFLOW  |  FE_UNDERFLOW) is non-zero, an exception has been raised. An application should
       either examine the return value or check the floating point exception flags to detect exceptions.

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |See below.		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

       The scalb() function is Standard. The scalbf() and scalbl() functions are Stable.

SEE ALSO

       feclearexcept(3M), fetestexcept(3M), ilogb(3M), ldexp(3M), logb(3M), math.h(3HEAD), matherr(3M), scalbln(3M), attributes(5), standards(5)

SunOS 5.10							    1 Nov 2003								 scalb(3M)

SCALB(P)						     POSIX Programmer's Manual							  SCALB(P)

NAME

       scalb - load exponent of a radix-independent floating-point number

SYNOPSIS

       #include <math.h>

       double scalb(double x, double n);

DESCRIPTION

       The  scalb()  function shall compute x*r**n, where r is the radix of the machine's floating-point arithmetic. When r is 2, scalb() shall be
       equivalent to ldexp() . The value of r is FLT_RADIX which is defined in <float.h>.

       An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT)  before  calling  these
       functions.   On	return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error
       has occurred.

RETURN VALUE

       Upon successful completion, the scalb() function shall return x*r**n.

       If x or n is NaN, a NaN shall be returned.

       If n is zero, x shall be returned.

       If x is +-Inf and n is not -Inf, x shall be returned.

       If x is +-0 and n is not +Inf, x shall be returned.

       If x is +-0 and n is +Inf, a domain error shall occur, and either a NaN	(if  supported),  or  an  implementation-defined  value  shall	be
       returned.

       If  x  is  +-Inf  and  n  is -Inf, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be
       returned.

       If the result would cause an overflow, a range error shall occur and +-HUGE_VAL (according to the sign of x) shall be returned.

       If the correct value would cause underflow, and is representable, a range error may occur and the correct value shall be returned.

       If the correct value would cause underflow, and is not representable, a range error may occur, and 0.0 shall be returned.

ERRORS

       The scalb() function shall fail if:

       Domain Error
	      If x is zero and n is +Inf, or x is Inf and n is -Inf.

       If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall	be  set  to  [EDOM].  If  the  integer	expression
       (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised.

       Range Error
	      The result would overflow.

       If  the	integer  expression  (math_errhandling	&  MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression
       (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised.

       The scalb() function may fail if:

       Range Error
	      The result underflows.

       If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set  to  [ERANGE].  If  the  integer	expression
       (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Applications should use either scalbln(), scalblnf(), or scalblnl() in preference to this function.

       IEEE Std 1003.1-2001  only  defines the behavior for the scalb() function when the n argument is an integer, a NaN, or Inf. The behavior of
       other values for the n argument is unspecified.

       On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of  each  other,  but	at
       least one of them must be non-zero.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       feclearexcept()	,  fetestexcept()  , ilogb() , ldexp() , logb() , scalbln() , the Base Definitions volume of IEEE Std 1003.1-2001, Section
       4.18, Treatment of Error Conditions for Mathematical Functions, <float.h>, <math.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								  SCALB(P)