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| author | Alejandro Colomar <alx@kernel.org> | 2024-04-26 15:06:49 +0200 |
|---|---|---|
| committer | Alejandro Colomar <alx@kernel.org> | 2024-05-02 01:24:19 +0200 |
| commit | dcde2f70372b49ec43efc5db864c9ff585d0a2dd (patch) | |
| tree | 78b9b7425130e4a5858e4c01a524d802423879ed /man/man3/logb.3 | |
| parent | 12aca537ce78a41bbcdaf485209691e10f8002d7 (diff) | |
| download | man-pages-dcde2f70372b49ec43efc5db864c9ff585d0a2dd.tar.gz | |
man/, share/mk/: Move man*/ to man/
This is a scripted change:
$ mkdir man/;
$ mv man* man/;
$ ln -st . man/man*;
$ find share/mk/ -type f \
| xargs grep -l '^MANDIR *:=' \
| xargs sed -i '/^MANDIR *:=/s,$,/man,';
$ find share/mk/dist/ -type f \
| xargs grep -l man \
| xargs sed -i 's,man%,man/%,g';
Link: <https://lore.kernel.org/linux-man/YxcV4h+Xn7cd6+q2@pevik/T/>
Cc: Petr Vorel <pvorel@suse.cz>
Cc: Jakub Wilk <jwilk@jwilk.net>
Cc: Stefan Puiu <stefan.puiu@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Diffstat (limited to 'man/man3/logb.3')
| -rw-r--r-- | man/man3/logb.3 | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/man/man3/logb.3 b/man/man3/logb.3 new file mode 100644 index 0000000000..6d1cb5be83 --- /dev/null +++ b/man/man3/logb.3 @@ -0,0 +1,142 @@ +'\" t +.\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>. +.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Inspired by a page by Walter Harms created 2002-08-10 +.\" +.TH logb 3 (date) "Linux man-pages (unreleased)" +.SH NAME +logb, logbf, logbl \- get exponent of a floating-point value +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include <math.h> +.P +.BI "double logb(double " x ); +.BI "float logbf(float " x ); +.BI "long double logbl(long double " x ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR logb (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.P +.BR logbf (), +.BR logbl (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.SH DESCRIPTION +These functions extract the exponent from the +internal floating-point representation of +.I x +and return it as a floating-point value. +The integer constant +.BR FLT_RADIX , +defined in +.IR <float.h> , +indicates the radix used for the system's floating-point representation. +If +.B FLT_RADIX +is 2, +.BI logb( x ) +is similar to +.BI floor(log2(fabs( x )))\f[R],\f[] +except that the latter may give an incorrect integer +due to intermediate rounding. +.P +If +.I x +is subnormal, +.BR logb () +returns the exponent +.I x +would have if it were normalized. +.SH RETURN VALUE +On success, these functions return the exponent of +.IR x . +.P +If +.I x +is a NaN, +a NaN is returned. +.P +If +.I x +is zero, then a pole error occurs, and the functions return +.RB \- HUGE_VAL , +.RB \- HUGE_VALF , +or +.RB \- HUGE_VALL , +respectively. +.P +If +.I x +is negative infinity or positive infinity, then +positive infinity is returned. +.SH ERRORS +See +.BR math_error (7) +for information on how to determine whether an error has occurred +when calling these functions. +.P +The following errors can occur: +.TP +Pole error: \fIx\fP is 0 +.\" .I errno +.\" is set to +.\" .BR ERANGE . +A divide-by-zero floating-point exception +.RB ( FE_DIVBYZERO ) +is raised. +.P +These functions do not set +.IR errno . +.\" FIXME . Is it intentional that these functions do not set errno? +.\" log(), log2(), log10() do set errno +.\" Bug raised: https://www.sourceware.org/bugzilla/show_bug.cgi?id=6793 +.\" +.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 logb (), +.BR logbf (), +.BR logbl () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +C99, POSIX.1-2001. +.TP +.BR logb () +4.3BSD +(see IEEE.3 in the 4.3BSD manual). +.SH SEE ALSO +.BR ilogb (3), +.BR log (3) |