# nextafter(3) [netbsd man page]

NEXTAFTER(3) BSD Library Functions Manual NEXTAFTER(3)NAME

nextafter, nextafterf, nextafterl, nexttowardnext representable floating-point number--LIBRARY

Math Library (libm, -lm)SYNOPSIS

#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);DESCRIPTION

The nextafter(), nextafterf(), and nextafterl() functions return the next machine representable number from x in direction of y. In other words, if y is less than x, the functions return the largest representable floating-point number less than x. When x equals y, the value of y is returned. The three functions differ only in the type of the return value and x. The nexttoward() function is equivalent to the nextafter() family of functions with two exceptions: 1. The second parameter has a type long double. 2. The return value is y converted to the type of the function, provided that x equals y.RETURN VALUES

Upon successful completion, the described functions return the next representable floating-point value as described above. If x is finite but an overflow would occur, a range error follows and the functions return +-HUGE_VAL, +-HUGE_VALF, or +-HUGE_VALL with the same sign as x. When either x or y is NaN, a NaN is returned. When x is not y but the function value is subnormal, zero, or underflows, a range error occurs, and either 0.0 or the correct function value (if representable) is returned.SEE ALSO

math(3)STANDARDS

The described functions conform to ISO/IEC 9899:1999 (``ISO C99'').BSD

September 18, 2011 BSD

## Check Out this Related Man Page

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

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

cc [ flag... ] file...[ 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);-lmDESCRIPTION

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 5.101 Nov 2003 nextafter(3M)