NEXTAFTER(3)               Linux Programmer's Manual              NEXTAFTER(3)

       nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl
       - floating-point number manipulation

       #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);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
           _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99
       nextafterf(), nextafterl():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99
       nexttoward(), nexttowardf(), nexttowardl():
           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
           _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99

       The nextafter(), nextafterf(), and nextafterl()  functions  return  the
       next representable floating-point value following x in the direction of
       y.  If y is less than x, these functions will return the largest repre-
       sentable number less than x.

       If x equals y, the functions return y.

       The  nexttoward(),  nexttowardf(),  and  nexttowardl() functions do the
       same as the corresponding nextafter() functions, except that they  have
       a long double second argument.

       On  success,  these  functions  return the next representable floating-
       point value after x in the direction of y.

       If x equals y, then y (cast to the same type as x) is returned.

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

       If x is finite, and the result would overflow, a  range  error  occurs,
       and  the  functions  return  HUGE_VAL, HUGE_VALF, or HUGE_VALL, respec-
       tively, with the correct mathematical sign.

       If x is not equal to y, and the correct function result would  be  sub-
       normal,  zero,  or underflow, a range error occurs, and either the cor-
       rect value (if it can be represented), or 0.0, is returned.

       See math_error(7) for information on how to determine whether an  error
       has occurred when calling these functions.

       The following errors can occur:

       Range error: result overflow
              An overflow floating-point exception (FE_OVERFLOW) is raised.

       Range error: result is subnormal or underflows
              An underflow floating-point exception (FE_UNDERFLOW) is raised.

       These functions do not set errno.

       For   an   explanation   of   the  terms  used  in  this  section,  see

       |Interface                    | Attribute     | Value   |
       |nextafter(), nextafterf(),   | Thread safety | MT-Safe |
       |nextafterl(), nexttoward(),  |               |         |
       |nexttowardf(), nexttowardl() |               |         |
       C99, POSIX.1-2001, POSIX.1-2008.  This function is defined in  IEC  559
       (and the appendix with recommended functions in IEEE 754/IEEE 854).

       In  glibc  version  2.5  and  earlier,  these functions do not raise an
       underflow floating-point (FE_UNDERFLOW)  exception  when  an  underflow


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       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at

GNU                               2015-04-19                      NEXTAFTER(3)
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