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

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ lround(), lroundf(), lroundl(), llround(), llroundf(), llroundl()           │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

       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.

       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.

       glibc 2.1.  C99, POSIX.1-2001.

       Math library (libm, -lm)

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

       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 (longlong in  the
       case of the ll* functions), then a domain error occurs, and the return value is unspecified.

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

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

       C11, POSIX.1-2008.

#include<math.h>longlround(doublex);longlroundf(floatx);longlroundl(longdoublex);longlongllround(doublex);longlongllroundf(floatx);longlongllroundl(longdoublex);

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

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