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Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html. 8 .\" This notice shall appear on any product containing this material. 9 .\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). 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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 12 .TH log10 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions" 13 .SH NAME 14 log10, log10f, log10l \- base 10 logarithm function 15 .SH SYNOPSIS 16 .LP 17 .nf 18 c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ] 19 #include <math.h> 20 21 \fBdouble\fR \fBlog10\fR(\fBdouble\fR \fIx\fR); 22 .fi 23 24 .LP 25 .nf 26 \fBfloat\fR \fBlog10f\fR(\fBfloat\fR \fIx\fR); 27 .fi 28 29 .LP 30 .nf 31 \fBlong double\fR \fBlog10l\fR(\fBlong double\fR \fIx\fR); 32 .fi 33 34 .SH DESCRIPTION 35 .sp 36 .LP 37 These functions compute the base 10 logarithm of \fIx\fR, log(10)(\fIx\fR). 38 .SH RETURN VALUES 39 .sp 40 .LP 41 Upon successful completion, \fBlog10()\fR returns the base 10 logarithm of 42 \fIx\fR. 43 .sp 44 .LP 45 If \fIx\fR is \(+-0, a pole error occurs and \fBlog10()\fR, \fBlog10f()\fR, and 46 \fBlog10l()\fR return \(mi\fBHUGE_VAL\fR, \(mi\fBHUGE_VALF\fR, and 47 \(mi\fBHUGE_VALL\fR, respectively. 48 .sp 49 .LP 50 For finite values of \fIx\fR that are less than 0, or if \fIx\fR is \(miInf, a 51 domain error occurs and a NaN is returned. 52 .sp 53 .LP 54 If \fIx\fR is NaN, a NaN is returned. 55 .sp 56 .LP 57 If \fIx\fR is 1, +0 is returned. 58 .sp 59 .LP 60 If \fIx\fR is +Inf, \fIx\fR is returned. 61 .sp 62 .LP 63 For exceptional cases, \fBmatherr\fR(3M) tabulates the values to be returned by 64 \fBlog10()\fR as specified by SVID3 and XPG3. 65 .SH ERRORS 66 .sp 67 .LP 68 These functions will fail if: 69 .sp 70 .ne 2 71 .mk 72 .na 73 \fBDomain Error\fR 74 .ad 75 .RS 16n 76 .rt 77 The finite value of \fIx\fR is negative, or \fIx\fR is -Inf. 78 .sp 79 If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is 80 non-zero, the invalid floating-point exception is raised. 81 .sp 82 The \fBlog10()\fR function sets \fBerrno\fR to \fBEDOM\fR if the value of 83 \fIx\fR is negative. 84 .RE 85 86 .sp 87 .ne 2 88 .mk 89 .na 90 \fBPole Error\fR 91 .ad 92 .RS 16n 93 .rt 94 The value of \fIx\fR is 0. 95 .sp 96 If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is 97 non-zero, the divide-by-zero floating-point exception is raised. 98 .RE 99 100 .SH USAGE 101 .sp 102 .LP 103 An application wanting to check for exceptions should call 104 \fBfeclearexcept\fR(\fBFE_ALL_EXCEPT\fR) before calling these functions. On 105 return, if \fBfetestexcept\fR(\fBFE_INVALID\fR | \fBFE_DIVBYZERO\fR | 106 \fBFE_OVERFLOW\fR | \fBFE_UNDERFLOW\fR) is non-zero, an exception has been 107 raised. An application should either examine the return value or check the 108 floating point exception flags to detect exceptions. 109 .sp 110 .LP 111 An application can also set \fBerrno\fR to 0 before calling \fBlog10()\fR. On 112 return, if \fBerrno\fR is non-zero, an error has occurred. The \fBlog10f()\fR 113 and \fBlog10l()\fR functions do not set \fBerrno\fR. 114 .SH ATTRIBUTES 115 .sp 116 .LP 117 See \fBattributes\fR(5) for descriptions of the following attributes: 118 .sp 119 120 .sp 121 .TS 122 tab() box; 123 cw(2.75i) |cw(2.75i) 124 lw(2.75i) |lw(2.75i) 125 . 126 ATTRIBUTE TYPEATTRIBUTE VALUE 127 _ 128 Interface StabilityStandard 129 _ 130 MT-LevelMT-Safe 131 .TE 132 133 .SH SEE ALSO 134 .sp 135 .LP 136 \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M), \fBisnan\fR(3M), 137 \fBlog\fR(3M), \fBmath.h\fR(3HEAD), \fBmatherr\fR(3M), \fBpow\fR(3M), 138 \fBattributes\fR(5), \fBstandards\fR(5)