man3/log10.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
   2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
   3 .\"     <mtk.manpages@gmail.com>
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  27 .\" References consulted:
  28 .\"     Linux libc source code
  29 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  30 .\"     386BSD man pages
  31 .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
  32 .\" Modified 1995-08-14 by Arnt Gulbrandsen <agulbra@troll.no>
  33 .\" Modified 2002-07-27 by Walter Harms
  34 .\"     (walter.harms@informatik.uni-oldenburg.de)
  35 .\"
  36 .TH LOG10 3  2010-09-20  "" "Linux Programmer's Manual"
  37 .SH NAME
  38 log10, log10f, log10l \-  base-10 logarithmic function
  39 .SH SYNOPSIS
  40 .nf
  41 .B #include <math.h>
  42 .sp
  43 .BI "double log10(double " x );
  44 .br
  45 .BI "float log10f(float " x );
  46 .br
  47 .BI "long double log10l(long double " x );
  48 .fi
  49 .sp
  50 Link with \fI\-lm\fP.
  51 .sp
  52 .in -4n
  53 Feature Test Macro Requirements for glibc (see
  54 .BR feature_test_macros (7)):
  55 .in
  56 .sp
  57 .ad l
  58 .BR log10f (),
  59 .BR log10l ():
  60 .RS 4
  61 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
  62 _POSIX_C_SOURCE\ >=\ 200112L;
  63 .br
  64 or
  65 .I cc\ -std=c99
  66 .RE
  67 .ad
  68 .SH DESCRIPTION
  69 The
  70 .BR log10 ()
  71 function returns the base 10 logarithm of \fIx\fP.
  72 .SH RETURN VALUE
  73 On success, these functions return the base 10 logarithm of
  74 .IR x .
  75
  76 For special cases, including where
  77 .I x
  78 is 0, 1, negative, infinity, or NaN, see
  79 .BR log (3).
  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
  86 For a discussion of the errors that can occur for these functions, see
  87 .BR log (3).
  88 .SH CONFORMING TO
  89 C99, POSIX.1-2001.
  90 The variant returning
  91 .I double
  92 also conforms to
  93 SVr4, 4.3BSD, C89.
  94 .SH SEE ALSO
  95 .BR cbrt (3),
  96 .BR clog10 (3),
  97 .BR exp10 (3),
  98 .BR log (3),
  99 .BR log2 (3),
 100 .BR sqrt (3)