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NAME
       lround, lroundf, lroundl - round to nearest integer value


SYNOPSIS
       #include <math.h>

       long lround(double x);
       long lroundf(float x);
       long lroundl(long double x);


DESCRIPTION
       These  functions shall round their argument to the nearest integer value, rounding halfway
       cases away from zero, regardless of the current rounding direction.

       An application wishing to check for error situations should set errno  to  zero  and  call
       feclearexcept(FE_ALL_EXCEPT)  before calling these functions.  On return, if errno is non-
       zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is  non-zero,
       an error has occurred.


RETURN VALUE
       Upon successful completion, these functions shall return the rounded integer value.

       If x is NaN, a domain error shall occur and an unspecified value is returned.

       If x is +Inf, a domain error shall occur and an unspecified value is returned.

       If x is -Inf, a domain error shall occur and an unspecified value is returned.

       If  the  correct  value  is  positive and too large to represent as a long, a domain error
       shall occur and an unspecified value is returned.

       If the correct value is negative and too large to represent as  a  long,  a  domain  error
       shall occur and an unspecified value is returned.


ERRORS
       These functions shall fail if:

       Domain Error
              The  x  argument  is  NaN  or ±Inf, or the correct value is not representable as an
              integer.

       If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be
       set  to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero,
       then the invalid floating-point exception shall be raised.

       The following sections are informative.


EXAMPLES
       None.


APPLICATION USAGE
       On  error,  the  expressions  (math_errhandling  &  MATH_ERRNO)  and  (math_errhandling  &
       MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.


RATIONALE
       These  functions differ from the lrint() functions in the default rounding direction, with
       the lround() functions rounding halfway cases away from zero and needing not to raise  the
       inexact  floating-point exception for non-integer arguments that round to within the range
       of the return type.


FUTURE DIRECTIONS
       None.


SEE ALSO
       feclearexcept()  ,  fetestexcept()  ,  llround()  ,  the  Base   Definitions   volume   of
       IEEE Std 1003.1-2001,  Section  4.18,  Treatment  of  Error  Conditions  for  Mathematical
       Functions, <math.h>


COPYRIGHT
       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2003  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .