Mathematical Library Functions nextafter(3M)
NAME
nextafter, nextafterf, nextafterl, nexttoward, nexttowardf,
nexttowardl - next representable double-precision floating-
point numberSYNOPSIS
c99 [ flag... ] file... -lm [ library... ]
#include
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() functionscompute the next representable floating-point value follow-
ing x in the direction of y. Thus, if y is less than x, nex-
tafter() returns the largest representable floating-point
number less than x. The nextafter(), nextafterf(), and nex-
tafterl() 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 nextrepresentable floating-point value following x in the direc-
tion of y. If x == y, y (of the type x) is returned.SunOS 5.11 Last change: 12 Jul 2006 1
Mathematical Library Functions nextafter(3M)If x is finite and the correct function value would over-
flow, 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 callfeclearexcept(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 nex-
tafter(). 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 attri-
butes:SunOS 5.11 Last change: 12 Jul 2006 2
Mathematical Library Functions nextafter(3M)____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| MT-Level | MT-Safe |
|_____________________________|_____________________________|
| Standard | See standards(5). ||_____________________________|_____________________________|
SEE ALSO
feclearexcept(3M), fetestexcept(3M), math.h(3HEAD), attri-
butes(5), standards(5)SunOS 5.11 Last change: 12 Jul 2006 3