Provided by: manpages-posix-dev_2.16-1_all bug

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 .