man3/fdim.3

   1 .\" Copyright 2003 Walter Harms, Andries Brouwer
   2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
   3 .\"     <mtk.manpages@gmail.com>
   4 .\"
   5 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
   6 .\" Distributed under GPL
   7 .\" %%%LICENSE_END
   8 .\"
   9 .TH FDIM 3 2015-04-19 "" "Linux Programmer's Manual"
  10 .SH NAME
  11 fdim, fdimf, fdiml \- positive difference
  12 .SH SYNOPSIS
  13 .B #include <math.h>
  14 .sp
  15 .BI "double fdim(double " x ", double " y );
  16 .br
  17 .BI "float fdimf(float " x ", float " y );
  18 .br
  19 .BI "long double fdiml(long double " x ", long double " y );
  20 .sp
  21 Link with \fI\-lm\fP.
  22 .sp
  23 .in -4n
  24 Feature Test Macro Requirements for glibc (see
  25 .BR feature_test_macros (7)):
  26 .in
  27 .sp
  28 .ad l
  29 .BR fdimf (),
  30 .BR fdiml ():
  31 .RS 4
  32 _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
  33 .br
  34 or
  35 .I cc\ -std=c99
  36 .RE
  37 .ad
  38 .SH DESCRIPTION
  39 These functions return the positive difference, max(\fIx\fP-\fIy\fP,0),
  40 between their arguments.
  41 .SH RETURN VALUE
  42 On success, these functions return the positive difference.
  43
  44 If
  45 .I x
  46 or
  47 .I y
  48 is a NaN, a NaN is returned.
  49
  50 If the result overflows,
  51 a range error occurs,
  52 and the functions return
  53 .BR HUGE_VAL ,
  54 .BR HUGE_VALF ,
  55 or
  56 .BR HUGE_VALL ,
  57 respectively.
  58 .SH ERRORS
  59 See
  60 .BR math_error (7)
  61 for information on how to determine whether an error has occurred
  62 when calling these functions.
  63 .PP
  64 The following errors can occur:
  65 .TP
  66 Range error: result overflow
  67 .\" .I errno
  68 .\" is set to
  69 .\" .BR ERANGE .
  70 An overflow floating-point exception
  71 .RB ( FE_OVERFLOW )
  72 is raised.
  73 .PP
  74 These functions do not set
  75 .IR errno .
  76 .\" FIXME . Is it intentional that these functions do not set errno?
  77 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6796
  78 .SH VERSIONS
  79 These functions first appeared in glibc in version 2.1.
  80 .SH ATTRIBUTES
  81 For an explanation of the terms used in this section, see
  82 .BR attributes (7).
  83 .TS
  84 allbox;
  85 lbw24 lb lb
  86 l l l.
  87 Interface       Attribute       Value
  88 T{
  89 .BR fdim (),
  90 .BR fdimf (),
  91 .BR fdiml ()
  92 T}      Thread safety   MT-Safe
  93 .TE
  94 .SH CONFORMING TO
  95 C99, POSIX.1-2001, POSIX.1-2008.
  96 .SH SEE ALSO
  97 .BR fmax (3)