\input texinfo.tex
@setfilename libm.info
@tex
% NOTE LOCAL KLUGE TO AVOID TOO MUCH WHITESPACE FROM "makedoc"
\global\long\def\example{%
\begingroup
\let\aboveenvbreak=\par
\let\afterenvbreak=\par
\parskip=0pt
\lisp}
\global\long\def\Eexample{%
\Elisp
\endgroup
\vskip -\parskip% to cancel out effect of following \par
}
% END LOCAL WHITESPACE KLUGE
@end tex
@syncodeindex fn cp

@ifinfo
@format
START-INFO-DIR-ENTRY
* libm::                        An ANSI-C conforming mathematical library.
END-INFO-DIR-ENTRY
@end format
@end ifinfo

@ifinfo
This file documents an ANSI-C conforming mathematical subroutine library.

Copyright (C) 1992, 1993, 1995 Cygnus Support

@file{libm} includes software developed at SunPro, a Sun Microsystems,
Inc. business.  Permission to use, copy, modify, and distribute this
software is freely granted, provided that this notice is preserved.

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.

@ignore
Permission is granted to process this file through Tex and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, subject to the terms
of the GNU General Public License, which includes the provision that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions.
@end ifinfo
@iftex
@finalout
@setchapternewpage odd
@settitle Cygnus C Math Library
@titlepage
@title The Cygnus C Math Library
@sp 1
@subtitle @code{libm} 1.4
@subtitle December 1995
@author {Steve Chamberlain}
@author {Roland Pesch}
@author {Cygnus Support}
@page

@tex
{\parskip=0pt
\hfill Cygnus Support\par
\hfill sac@@cygnus.com\par
\hfill pesch@@cygnus.com\par
}
\global\parindent=0pt % Steve likes it this way
@end tex

@vskip 0pt plus 1filll
Copyright @copyright{} 1992, 1993 Cygnus Support

@file{libm} includes software developed at SunPro, a Sun Microsystems,
Inc. business.  Permission to use, copy, modify, and distribute this
software is freely granted, provided that this notice is preserved.

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, subject to the terms
of the GNU General Public License, which includes the provision that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions.
@end titlepage
@end iftex

@ifinfo
@node Top
@top LIBM
@end ifinfo

@menu
* Math::           The mathematical functions (`math.h').
* Reentrancy::     The functions in libm are not reentrant by default.
* Index::
@end menu

@include targetdep.texi

@node Reentrancy
@chapter Reentrancy Properties of @code{libm}

@cindex reentrancy
@cindex @code{matherr} and reentrancy
When a libm function detects an exceptional case, @code{errno} may be
set, the @code{matherr} function may be called, and a error message 
may be written to the standard error stream.  This behavior may not
be reentrant.

@c The exact behavior depends on the currently selected error handling 
@c mode (IEEE, POSIX, X/Open, or SVID).

With reentrant C libraries like the Cygnus C library, @code{errno} is
a macro which expands to the per-thread error value.  This makes it thread
safe.

When the user provides his own @code{matherr} function it must be
reentrant for the math library as a whole to be reentrant.

In normal debugged programs, there are usually no math subroutine
errors---and therefore no assignments to @code{errno} and no @code{matherr}
calls; in that situation, the math functions behave reentrantly.

@node Index
@unnumbered Index
@printindex cp

@tex
% I think something like @@colophon should be in texinfo.  In the
% meantime:
\long\def\colophon{\hbox to0pt{}\vfill
\centerline{The body of this manual is set in}
\centerline{\fontname\tenrm,}
\centerline{with headings in {\bf\fontname\tenbf}}
\centerline{and examples in {\tt\fontname\tentt}.}
\centerline{{\it\fontname\tenit\/} and}
\centerline{{\sl\fontname\tensl\/}}
\centerline{are used for emphasis.}\vfill}
\page\colophon
% Blame: pesch@@cygnus.com, 28mar91.
@end tex

@contents
@bye


