PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       llround, llroundf, llroundl — round to nearest integer value

SYNOPSIS

       #include <math.h>

       long long llround(double x);
       long long llroundf(float x);
       long long llroundl(long double x);

DESCRIPTION

       The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is  unintentional.
       This volume of POSIX.1‐2017 defers to the ISO C standard.

       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 long, an unspecified
       value shall be returned.  On systems that support the IEC 60559 Floating-Point  option,  a
       domain error shall occur; otherwise, a domain error may occur.

       If the correct value is negative and too large to represent as a long long, an unspecified
       value shall be returned.  On systems that support the IEC 60559 Floating-Point  option,  a
       domain error shall occur; otherwise, a domain error may occur.

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.

       These functions may fail if:

       Domain Error
                   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 llrint() functions in that the default rounding direction
       for the llround() functions round halfway cases away from zero  and  need  not  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(), lround()

       The Base Definitions volume of POSIX.1‐2017, Section 4.20, Treatment of  Error  Conditions
       for Mathematical Functions, <math.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1-2017, Standard for Information Technology -- Portable  Operating  System  Interface
       (POSIX),  The  Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .