Manpages - lround.3

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

  #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

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.

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.

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.

These functions first appeared in glibc in version 2.1.

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

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

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

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