nextafter(3M)						  Mathematical Library Functions					     nextafter(3M)

NAME

       nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl - next representable double-precision floating-point number

SYNOPSIS

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

       double nextafter(double x, double y);

       float nextafterf(float x, float y);

       long double nextafterl(long double x, long double y);

       double nexttoward(double x, long double y);

       float nexttowardf(float x, long double y);

       long double nexttowardl(long double x, long double y);

DESCRIPTION

       The  nextafter(), nextafterf(), and nextafterl() functions compute the next representable floating-point value following x in the direction
       of y. Thus, if y is less than x, nextafter() returns the  largest  representable  floating-point  number  less  than  x.  The  nextafter(),
       nextafterf(), and nextafterl() functions return y if x equals y.

       The  nexttoward(),  nexttowardf(),  and	nexttowardl() functions are equivalent to the corresponding nextafter() functions, except that the
       second parameter has type long double and the functions return y converted to the type of the function if x equals y.

RETURN VALUES

       Upon successful completion, these functions return the next representable floating-point value following x in the direction of y.

       If x == y, y (of the type x) is returned.

       If x is finite and the correct function value would overflow, a range error occurs and +-HUGE_VAL, +-HUGE_VALF, and +-HUGE_VALL	(with  the
       same sign as x) is returned as appropriate for the return type of the function.

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

       If  x != y and the correct function value is subnormal, zero, or underflows, a range error occurs and either the correct function value (if
       representable) or 0.0 is returned.

ERRORS

       These functions will fail if:

       Range Error     The correct value overflows.

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

		       The nextafter() function sets errno to ERANGE if the correct value would overflow.

       Range Error     The correct value underflows.

		       If the integer expression (math_errhandling & MATH_ERREXCEPT)  is  non-zero,  the  underflow  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.

       An  application	can  also  set	errno  to  0  before  calling  nextafter().  On  return,  if errno is non-zero, an error has occurred. The
       nextafterf(), nextafterl(). nexttoward(), nexttowardf(), and nexttowardl() functions do not set errno.

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       feclearexcept(3M), fetestexcept(3M), math.h(3HEAD), attributes(5), standards(5)

SunOS 5.10							    1 Nov 2003							     nextafter(3M)