lround(3) — Linux manual page

lround(3)               Library Functions Manual               lround(3)

NAME

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

LIBRARY

       Math library (libm, -lm)

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);

   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.

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()   │               │         │
       └─────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       C11, POSIX.1-2008.

HISTORY

       glibc 2.1.  C99, POSIX.1-2001.

SEE ALSO

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

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                      lround(3)

Pages that refer to this page: lrint(3), round(3), roundup(3)

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