linux man page for nextafterf

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

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

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);
       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)):

       nextafter():
	   _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _ISOC99_SOURCE ||
	   _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

DESCRIPTION
       The nextafter() 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 representable number less than x.

       If x equals y, the functions return y.

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

RETURN VALUE
       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 subnormal, zero, or underflow, a range error occurs, and either  the  cor-
       rect value (if it can be represented), or 0.0, is returned.

ERRORS
       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.

CONFORMING TO
       C99, POSIX.1-2001.  This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).

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

SEE ALSO
       nearbyint(3)

COLOPHON
       This page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

GNU
								    2010-09-20							      NEXTAFTER(3)