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diff --git a/man3/log2.3 b/man3/log2.3 new file mode 100644 index 0000000..223ac99 --- /dev/null +++ b/man3/log2.3 @@ -0,0 +1,94 @@ +'\" t +.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) +.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" References consulted: +.\" Linux libc source code +.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) +.\" 386BSD man pages +.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) +.\" Modified 1995-08-14 by Arnt Gulbrandsen <agulbra@troll.no> +.\" Modified 2002-07-27 by Walter Harms +.\" (walter.harms@informatik.uni-oldenburg.de) +.\" +.TH log2 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +log2, log2f, log2l \- base-2 logarithmic function +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include <math.h> +.PP +.BI "double log2(double " x ); +.BI "float log2f(float " x ); +.BI "long double log2l(long double " x ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR log2 (), +.BR log2f (), +.BR log2l (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L +.fi +.SH DESCRIPTION +These functions return the base 2 logarithm of +.IR x . +.SH RETURN VALUE +On success, these functions return the base 2 logarithm of +.IR x . +.PP +For special cases, including where +.I x +is 0, 1, negative, infinity, or NaN, see +.BR log (3). +.SH ERRORS +See +.BR math_error (7) +for information on how to determine whether an error has occurred +when calling these functions. +.PP +For a discussion of the errors that can occur for these functions, see +.BR log (3). +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR log2 (), +.BR log2f (), +.BR log2l () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +glibc 2.1. +C99, POSIX.1-2001. +.PP +The variant returning +.I double +also conforms to +SVr4, 4.3BSD. +.SH SEE ALSO +.BR cbrt (3), +.BR clog2 (3), +.BR log (3), +.BR log10 (3), +.BR sqrt (3) |