.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .\" References consulted: .\" Linux libc source code .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified Sat Jul 24 19:42:57 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Aug 14 1995 by Arnt Gulbrandsen .TH EXP 3 "June 16, 1993" "GNU" "Linux Programmer's Manual" .SH NAME exp, log, log10, pow \- exponential, logarithmic and power functions .SH SYNOPSIS .nf .B #include .sp .BI "double exp(double " x ); .sp .BI "double log(double " x ); .sp .BI "double log10(double " x ); .sp .BI "double pow(double " x ", double " y ); .fi .SH DESCRIPTION The \fBexp()\fP function returns the value of e (the base of natural logarithms) raised to the power of \fIx\fP. .PP The \fBlog()\fP function returns the natural logarithm of \fIx\fP. .PP The \fBlog10()\fP function returns the base-10 logarithm of \fIx\fP. .PP The \fBpow()\fP function returns the value of \fIx\fP raised to the power of \fIy\fP. .SH "ERRORS" The \fBlog()\fP and \fBlog10()\fP functions can return the following errors: .TP .B EDOM The argument \fIx\fP is negative. .TP .B ERANGE The argument \fIx\fP is zero. The log of zero is not defined. .PP The \fBpow()\fP function can return the following error: .TP .B EDOM The argument \fIx\fP is negative and \fIy\fP is not an integral value. This would result in a complex number. .SH "CONFORMING TO" SVID 3, POSIX, BSD 4.3, ISO 9899 .SH "SEE ALSO" .BR sqrt "(3), " cbrt (3)