NAME

       lround, lroundf, lroundl, llround, llroundf, llroundl - round to nearest integer

SYNOPSIS

       #include <math.h>

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

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

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       All functions shown above:
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION

       These  functions round their argument to the nearest integer value, rounding halfway cases
       away from zero, regardless of the current rounding direction (see fenv(3)).

       Note that unlike the round(3) and ceil(3), functions, the return type of  these  functions
       differs from that of their arguments.

RETURN VALUE

       These functions return the rounded integer value.

       If  x  is  a  NaN or an infinity, or the rounded value is too large to be stored in a long
       (long long in the case of the ll* functions), then a domain error occurs, and  the  return
       value is unspecified.

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:

       Domain error: x is a NaN or infinite, or the rounded value is too large
              An invalid floating-point exception (FE_INVALID) is raised.

       These functions do not set errno.

VERSIONS

       These functions first appeared in glibc in version 2.1.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────┬───────────────┬─────────┐
       │Interface                         │ Attribute     │ Value   │
       ├──────────────────────────────────┼───────────────┼─────────┤
       │lround(), lroundf(), lroundl(),   │ Thread safety │ MT-Safe │
       │llround(), llroundf(), llroundl() │               │         │
       └──────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

       C99, POSIX.1-2001, POSIX.1-2008.

SEE ALSO

       ceil(3), floor(3), lrint(3), nearbyint(3), rint(3), round(3)

COLOPHON

       This page is part of release 5.10 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at https://www.kernel.org/doc/man-pages/.

                                            2020-11-01                                  LROUND(3)