llround(3)

1lround(3)                  Library Functions Manual                  lround(3)
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NAME

6       lround,  lroundf, lroundl, llround, llroundf, llroundl - round to near‐
7       est integer
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LIBRARY

10       Math library (libm, -lm)
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SYNOPSIS

13       #include <math.h>
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15       long lround(double x);
16       long lroundf(float x);
17       long lroundl(long double x);
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19       long long llround(double x);
20       long long llroundf(float x);
21       long long llroundl(long double x);
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23   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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25       All functions shown above:
26           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
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DESCRIPTION

29       These functions round their argument  to  the  nearest  integer  value,
30       rounding halfway cases away from zero, regardless of the current round‐
31       ing direction (see fenv(3)).
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33       Note that unlike the round(3) and ceil(3), functions, the  return  type
34       of these functions differs from that of their arguments.
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RETURN VALUE

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

44       See  math_error(7) for information on how to determine whether an error
45       has occurred when calling these functions.
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47       The following errors can occur:
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49       Domain error: x is a NaN or infinite, or the rounded value is too large
50              An invalid floating-point exception (FE_INVALID) is raised.
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52       These functions do not set errno.
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ATTRIBUTES

55       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
56       tributes(7).
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58       ┌────────────────────────────────────────────┬───────────────┬─────────┐
59       │Interface                                   │ Attribute     │ Value   │
60       ├────────────────────────────────────────────┼───────────────┼─────────┤
61       │lround(), lroundf(), lroundl(), llround(),  │ Thread safety │ MT-Safe │
62       │llroundf(), llroundl()                      │               │         │
63       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

66       C11, POSIX.1-2008.
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HISTORY

69       glibc 2.1.  C99, POSIX.1-2001.
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