nextafter(3) - NetBSD Manual Pages

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NEXTAFTER(3)            NetBSD Library Functions Manual           NEXTAFTER(3)


NAME

     nextafter, nextafterf, nextafterl, nexttoward -- next 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 rep-
     resentable 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 func-
     tion 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'').

NetBSD 6.0.4                  September 18, 2011                  NetBSD 6.0.4