man3/lrint.3

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  27 .TH LRINT 3  2017-09-15 "" "Linux Programmer's Manual"
  28 .SH NAME
  29 lrint, lrintf, lrintl, llrint, llrintf, llrintl \- round to nearest integer
  30 .SH SYNOPSIS
  31 .nf
  32 .B #include <math.h>
  33 .PP
  34 .BI "long int lrint(double " x );
  35 .BI "long int lrintf(float " x );
  36 .BI "long int lrintl(long double " x );
  37 .PP
  38 .BI "long long int llrint(double " x );
  39 .BI "long long int llrintf(float " x );
  40 .BI "long long int llrintl(long double " x );
  41 .fi
  42 .PP
  43 Link with \fI\-lm\fP.
  44 .PP
  45 .in -4n
  46 Feature Test Macro Requirements for glibc (see
  47 .BR feature_test_macros (7)):
  48 .in
  49 .PP
  50 .ad l
  51 All functions shown above:
  52 .RS 4
  53 _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
  54 .RE
  55 .ad
  56 .SH DESCRIPTION
  57 These functions round their argument to the nearest integer value,
  58 using the current rounding direction (see
  59 .BR fesetround (3)).
  60 .PP
  61 Note that unlike the
  62 .BR rint (3)
  63 family of functions,
  64 the return type of these functions differs from
  65 that of their arguments.
  66 .SH RETURN VALUE
  67 These functions return the rounded integer value.
  68 .PP
  69 If
  70 .I x
  71 is a NaN or an infinity,
  72 or the rounded value is too large to be stored in a
  73 .I long
  74 .RI ( "long long"
  75 in the case of the
  76 .B ll*
  77 functions),
  78 then a domain error occurs, and the return value is unspecified.
  79 .\" The return value is -(LONG_MAX - 1) or -(LLONG_MAX -1)
  80 .SH ERRORS
  81 See
  82 .BR math_error (7)
  83 for information on how to determine whether an error has occurred
  84 when calling these functions.
  85 .PP
  86 The following errors can occur:
  87 .TP
  88 Domain error: \fIx\fP is a NaN or infinite, or the rounded value is too large
  89 .\" .I errno
  90 .\" is set to
  91 .\" .BR EDOM .
  92 An invalid floating-point exception
  93 .RB ( FE_INVALID )
  94 is raised.
  95 .PP
  96 These functions do not set
  97 .IR errno .
  98 .\" FIXME . Is it intentional that these functions do not set errno?
  99 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6798
 100 .SH VERSIONS
 101 These functions first appeared in glibc in version 2.1.
 102 .SH ATTRIBUTES
 103 For an explanation of the terms used in this section, see
 104 .BR attributes (7).
 105 .TS
 106 allbox;
 107 lbw30 lb lb
 108 l l l.
 109 Interface       Attribute       Value
 110 T{
 111 .BR lrint (),
 112 .BR lrintf (),
 113 .BR lrintl (),
 114 .br
 115 .BR llrint (),
 116 .BR llrintf (),
 117 .BR llrintl ()
 118 T}      Thread safety   MT-Safe
 119 .TE
 120 .SH CONFORMING TO
 121 C99, POSIX.1-2001, POSIX.1-2008.
 122 .SH SEE ALSO
 123 .BR ceil (3),
 124 .BR floor (3),
 125 .BR lround (3),
 126 .BR nearbyint (3),
 127 .BR rint (3),
 128 .BR round (3)