man3/lrint.3

   1 .\" Copyright 2001 Andries Brouwer <aeb@cwi.nl>.
   2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
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  25 .TH LRINT 3  2008-08-05 "" "Linux Programmer's Manual"
  26 .SH NAME
  27 lrint, lrintf, lrintl, llrint, llrintf, llrintl \- round to nearest integer
  28 .SH SYNOPSIS
  29 .nf
  30 .B #include <math.h>
  31 .sp
  32 .BI "long int lrint(double " x );
  33 .br
  34 .BI "long int lrintf(float " x );
  35 .br
  36 .BI "long int lrintl(long double " x );
  37 .sp
  38 .BI "long long int llrint(double " x );
  39 .br
  40 .BI "long long int llrintf(float " x );
  41 .br
  42 .BI "long long int llrintl(long double " x );
  43 .fi
  44 .sp
  45 Link with \fI\-lm\fP.
  46 .sp
  47 .in -4n
  48 Feature Test Macro Requirements for glibc (see
  49 .BR feature_test_macros (7)):
  50 .in
  51 .sp
  52 .ad l
  53 All functions shown above:
  54 _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
  55 .I cc\ -std=c99
  56 .ad b
  57 .SH DESCRIPTION
  58 These functions round their argument to the nearest integer value,
  59 using the current rounding direction (see
  60 .BR fesetround (3)).
  61
  62 Note that unlike
  63 .BR rint (3),
  64 etc., 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
  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 "CONFORMING TO"
 101 C99, POSIX.1-2001.
 102 .SH "SEE ALSO"
 103 .BR ceil (3),
 104 .BR floor (3),
 105 .BR lround (3),
 106 .BR nearbyint (3),
 107 .BR rint (3),
 108 .BR round (3)