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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  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.
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 appen-
       dix 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 3.53 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)