BSD 4_4 release

[unix-history] / usr / src / lib / libm / common_source / infnan.3

diff --git a/usr/src/lib/libm/common_source/infnan.3 b/usr/src/lib/libm/common_source/infnan.3
index f7cc1f6..6a94bf6 100644 (file)
--- a/usr/src/lib/libm/common_source/infnan.3
+++ b/usr/src/lib/libm/common_source/infnan.3
@@ -1,87 +1,149 @@
-.\" Copyright (c) 1985 Regents of the University of California.
-.\" All rights reserved.  The Berkeley software License Agreement
-.\" specifies the terms and conditions for redistribution.
+.\" Copyright (c) 1985, 1991, 1993
+.\"    The Regents of the University of California.  All rights reserved.

 .\"
 .\"

-.\"    @(#)infnan.3    6.2 (Berkeley) %G%
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"    This product includes software developed by the University of
+.\"    California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.

 .\"
 .\"

-.TH INFNAN 3M  ""
-.UC 6
-.ds nn \fINaN\fR
-.SH NAME
-infnan \- signals invalid floating-point operations on a VAX (temporary)
-.SH SYNOPSIS
-.nf
-.B #include <math.h>
-.PP
-.B double infnan(iarg)
-.B int iarg;
-.SH DESCRIPTION
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)infnan.3   8.1 (Berkeley) 6/4/93
+.\"
+.Dd June 4, 1993
+.Dt INFNAN 3
+.Os BSD 4.3
+.Sh NAME
+.Nm infnan
+.Nd signals invalid floating\-point operations on a
+.Tn VAX
+(temporary)
+.Sh SYNOPSIS
+.Fd #include <math.h>
+.Ft double 
+.Fn infnan "int iarg"
+.Sh DESCRIPTION

 At some time in the future, some of the useful properties of
 At some time in the future, some of the useful properties of

-the Infinities and \*(nns in the IEEE standard 754 for Binary
-Floating\-Point Arithmetic will be simulated in UNIX on the
-DEC VAX by using its Reserved Operands.  Meanwhile, the
+the Infinities and \*(Nas in the
+.Tn IEEE
+standard 754 for Binary
+Floating\-Point Arithmetic will be simulated in
+.Tn UNIX
+on the
+.Tn DEC VAX
+by using its Reserved Operands.  Meanwhile, the

 Invalid, Overflow and Divide\-by\-Zero exceptions of the
 Invalid, Overflow and Divide\-by\-Zero exceptions of the

-IEEE standard are being approximated on a VAX by calls to a
-procedure \fIinfnan\fR in appropriate places in \fIlibm\fR.  When
-better exception\-handling is implemented in UNIX, only
-\fIinfnan\fR among the codes in \fIlibm\fR will have to be changed.
-And users of \fIlibm\fR can design their own \fIinfnan\fR now to
+.Tn IEEE
+standard are being approximated on a
+.Tn VAX
+by calls to a
+procedure
+.Fn infnan
+in appropriate places in
+.Xr libm 3 .
+When
+better exception\-handling is implemented in
+.Tn UNIX , 
+only
+.Fn infnan
+among the codes in
+.Xr libm
+will have to be changed.
+And users of
+.Xr libm
+can design their own
+.Fn infnan
+now to

 insulate themselves from future changes.
 insulate themselves from future changes.

-.PP
-Whenever an elementary function code in \fIlibm\fR has to
-simulate one of the aforementioned IEEE exceptions, it calls
-infnan(iarg) with an appropriate value of \fIiarg\fR.  Then a
-reserved operand fault stops computation.  But \fIinfnan\fR could
+.Pp
+Whenever an elementary function code in
+.Xr libm
+has to
+simulate one of the aforementioned
+.Tn IEEE
+exceptions, it calls
+.Fn infnan iarg
+with an appropriate value of
+.Fa iarg .
+Then a
+reserved operand fault stops computation.  But
+.Fn infnan
+could

 be replaced by a function with the same name that returns
 some plausible value, assigns an apt value to the global
 be replaced by a function with the same name that returns
 some plausible value, assigns an apt value to the global

-variable \fIerrno\fR, and allows computation to resume.
+variable
+.Va errno ,
+and allows computation to resume.

 Alternatively, the Reserved Operand Fault Handler could be
 Alternatively, the Reserved Operand Fault Handler could be

-changed to respond by returning that plausible value etc.
+changed to respond by returning that plausible value, etc.

 instead of aborting.
 instead of aborting.

-.PP
+.Pp

 In the table below, the first two columns show various
 In the table below, the first two columns show various

-exceptions signaled by the IEEE standard, and the default
+exceptions signaled by the
+.Tn IEEE
+standard, and the default

 result it prescribes.  The third column shows what value is
 result it prescribes.  The third column shows what value is

-given to \fIiarg\fR by functions in \fIlibm\fR when they
-invoke infnan(iarg) under analogous circumstances on a VAX.
-Currently \fIinfnan\fR stops computation under all those
+given to
+.Fa iarg
+by functions in
+.Xr libm
+when they
+invoke
+.Fn infnan iarg
+under analogous circumstances on a
+.Tn VAX . 
+Currently
+.Fn infnan
+stops computation under all those

 circumstances.  The last two columns offer an alternative;
 circumstances.  The last two columns offer an alternative;

-they suggest a setting for \fIerrno\fR and a value for a
-revised \fIinfnan\fR to return.  And a C program to
+they suggest a setting for
+.Va errno
+and a value for a
+revised
+.Fn infnan
+to return.  And a C program to

 implement that suggestion follows. 
 .sp 0.5
 implement that suggestion follows. 
 .sp 0.5

-.RS
-.nf
-.ta \w'Div\-by\-0'u+2n +\w'+Infinity'u+1n +\w'+ERANGE'u+1n +\w'ERANGE or EDOM'u+4n +\w'+HUGE'u+1n
-IEEE   IEEE
-Signal Default \fIiarg\fR      \fIerrno\fR     \fIinfnan\fR
-.if t \{\
-.sp -0.5
-.ta \w'Div\-by\-0'u+2n+\w'+Infinity'u+1n+\w'+ERANGE'u+1n+\w'ERANGE or EDOM'u+4n+\w'+HUGE'u+1n
-.tc \(ru
-       
-.ta \w'Div\-by\-0'u+2n +\w'+Infinity'u+1n +\w'+ERANGE'u+1n +\w'ERANGE or EDOM'u+4n +\w'+HUGE'u+1n
-.tc \}
-.if n \
-\l'5i'
-Invalid        \*(nn   EDOM    EDOM    0
-.if n \{\
-Overflow       \(+-Infinity    ERANGE  ERANGE  HUGE
-Div\-by\-0     \(+-Infinity    \(+-ERANGE      ERANGE or EDOM  \(+-HUGE \}
-.if t \{\
-Overflow       \(+-\(if        ERANGE  ERANGE  HUGE
-Div\-by\-0     \(+-\(if        \(+-ERANGE      ERANGE or EDOM  \(+-HUGE \}
-.sp 0.5
-       (HUGE = 1.7e38 ... nearly  2.0**127)
-.ta
-.fi
-.RE
-.sp 0.5
-.PP
-.nf
-.ta \w'\fBextern int\fR'u+1n +\w'\fBdefault:\fR'u+1n +\w'\fB\-ERANGE:\fR'u+1n +\w'\fBerrno = ERANGE;\fR'u+1n
-ALTERNATIVE  \fIinfnan\fR:\fB
-.sp 0.5
+.Bd -filled -offset indent
+.Bl -column "IEEE Signal" "IEEE Default" XXERANGE ERANGEXXorXXEDOM
+.It IEEE Signal        IEEE Default Ta
+.Fa iarg Ta
+.Va errno Ta
+.Fn infnan
+.It Invalid    \*(Na Ta
+.Dv EDOM       EDOM    0
+.It Overflow   \(+-\*(If Ta
+.Dv ERANGE     ERANGE  HUGE
+.It Div\-by\-0 \(+-Infinity Ta
+.Dv \(+-ERANGE ERANGE or EDOM  \(+-HUGE
+.It    ( Ns Dv HUGE No "= 1.7e38 ... nearly  2.0**127)"
+.El
+.Ed
+.Pp
+ALTERNATIVE
+.Fn infnan :
+.Bd -literal -offset indent

 #include       <math.h>
 #include       <errno.h>
 extern int     errno ;
 #include       <math.h>
 #include       <errno.h>
 extern int     errno ;


@@ -89,16 +151,30 @@ double     infnan(iarg)
 int    iarg ;
 {
        switch(iarg) {
 int    iarg ;
 {
        switch(iarg) {

-       case    \0ERANGE:       errno = ERANGE; return(HUGE);
+       case    \0ERANGE:       errno = ERANGE; return(HUGE);

        case    \-ERANGE:       errno = EDOM;   return(\-HUGE);
        default:                errno = EDOM;   return(0);
        }
        case    \-ERANGE:       errno = EDOM;   return(\-HUGE);
        default:                errno = EDOM;   return(0);
        }

-}\fR
-.ta
-.fi
-.SH SEE ALSO
-intro(3M), intro(2), signal(3).
-.PP
-ERANGE and EDOM are defined in <errno.h>.  See intro(2)
-for interpretations of EDOM and ERANGE from the operating
-system's point of view.
+}
+.Ed
+.Sh SEE ALSO
+.Xr math 3 ,
+.Xr intro 2 ,
+.Xr signal 3 .
+.Pp
+.Dv ERANGE
+and
+.Dv EDOM
+are defined in
+.Aq Pa errno.h .
+(See
+.Xr intro 2
+for explanation of
+.Dv EDOM
+and
+.Dv ERANGE . )
+.Sh HISTORY
+The
+.Fn infnan
+function appeared in 
+.Bx 4.3 .