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 2016-03-15 "" "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 .RE
  34 .ad
  35 .SH DESCRIPTION
  36 These functions return the positive difference, max(\fIx\fP-\fIy\fP,0),
  37 between their arguments.
  38 .SH RETURN VALUE
  39 On success, these functions return the positive difference.
  40
  41 If
  42 .I x
  43 or
  44 .I y
  45 is a NaN, a NaN is returned.
  46
  47 If the result overflows,
  48 a range error occurs,
  49 and the functions return
  50 .BR HUGE_VAL ,
  51 .BR HUGE_VALF ,
  52 or
  53 .BR HUGE_VALL ,
  54 respectively.
  55 .SH ERRORS
  56 See
  57 .BR math_error (7)
  58 for information on how to determine whether an error has occurred
  59 when calling these functions.
  60 .PP
  61 The following errors can occur:
  62 .TP
  63 Range error: result overflow
  64 .\" .I errno
  65 .\" is set to
  66 .\" .BR ERANGE .
  67 An overflow floating-point exception
  68 .RB ( FE_OVERFLOW )
  69 is raised.
  70 .PP
  71 These functions do not set
  72 .IR errno .
  73 .\" FIXME . Is it intentional that these functions do not set errno?
  74 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6796
  75 .SH VERSIONS
  76 These functions first appeared in glibc in version 2.1.
  77 .SH ATTRIBUTES
  78 For an explanation of the terms used in this section, see
  79 .BR attributes (7).
  80 .TS
  81 allbox;
  82 lbw24 lb lb
  83 l l l.
  84 Interface       Attribute       Value
  85 T{
  86 .BR fdim (),
  87 .BR fdimf (),
  88 .BR fdiml ()
  89 T}      Thread safety   MT-Safe
  90 .TE
  91 .SH CONFORMING TO
  92 C99, POSIX.1-2001, POSIX.1-2008.
  93 .SH SEE ALSO
  94 .BR fmax (3)