BSD 4_3_Net_2 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 9e4fe19..5dbd8ed 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 Regents of the University of California.
+.\" All rights reserved.

 .\"
 .\"

-.\"    @(#)infnan.3    6.4 (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   6.5 (Berkeley) 4/19/91
+.\"
+.Dd April 19, 1991
+.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
 changed to respond by returning that plausible value, etc.
 instead of aborting.
 Alternatively, the Reserved Operand Fault Handler could be
 changed to respond by returning that plausible value, etc.
 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 ;


@@ -89,15 +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
-math(3M), intro(2), signal(3).
-.PP
-ERANGE and EDOM are defined in <errno.h>.  See intro(2)
-for explanation of EDOM and ERANGE.
+}
+.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 .