mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-28 05:51:04 +00:00
124 lines
3.0 KiB
C
124 lines
3.0 KiB
C
|
|
/* @(#)s_matherr.c 5.1 93/09/24 */
|
|
/*
|
|
* ====================================================
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* 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.
|
|
* ====================================================
|
|
*/
|
|
|
|
/*
|
|
|
|
FUNCTION
|
|
<<matherr>>---modifiable math error handler
|
|
|
|
INDEX
|
|
matherr
|
|
|
|
ANSI_SYNOPSIS
|
|
#include <math.h>
|
|
int matherr(struct exception *<[e]>);
|
|
|
|
TRAD_SYNOPSIS
|
|
#include <math.h>
|
|
int matherr(*<[e]>)
|
|
struct exception *<[e]>;
|
|
|
|
DESCRIPTION
|
|
<<matherr>> is called whenever a math library function generates an error.
|
|
You can replace <<matherr>> by your own subroutine to customize
|
|
error treatment. The customized <<matherr>> must return 0 if
|
|
it fails to resolve the error, and non-zero if the error is resolved.
|
|
|
|
When <<matherr>> returns a nonzero value, no error message is printed
|
|
and the value of <<errno>> is not modified. You can accomplish either
|
|
or both of these things in your own <<matherr>> using the information
|
|
passed in the structure <<*<[e]>>>.
|
|
|
|
This is the <<exception>> structure (defined in `<<math.h>>'):
|
|
. struct exception {
|
|
. int type;
|
|
. char *name;
|
|
. double arg1, arg2, retval;
|
|
. int err;
|
|
. };
|
|
|
|
The members of the exception structure have the following meanings:
|
|
o+
|
|
o type
|
|
The type of mathematical error that occured; macros encoding error
|
|
types are also defined in `<<math.h>>'.
|
|
|
|
o name
|
|
a pointer to a null-terminated string holding the
|
|
name of the math library function where the error occurred.
|
|
|
|
o arg1, arg2
|
|
The arguments which caused the error.
|
|
|
|
o retval
|
|
The error return value (what the calling function will return).
|
|
|
|
o err
|
|
If set to be non-zero, this is the new value assigned to <<errno>>.
|
|
o-
|
|
|
|
The error types defined in `<<math.h>>' represent possible mathematical
|
|
errors as follows:
|
|
|
|
o+
|
|
o DOMAIN
|
|
An argument was not in the domain of the function; e.g. <<log(-1.0)>>.
|
|
|
|
o SING
|
|
The requested calculation would result in a singularity; e.g. <<pow(0.0,-2.0)>>
|
|
|
|
o OVERFLOW
|
|
A calculation would produce a result too large to represent; e.g.
|
|
<<exp(1000.0)>>.
|
|
|
|
o UNDERFLOW
|
|
A calculation would produce a result too small to represent; e.g.
|
|
<<exp(-1000.0)>>.
|
|
|
|
o TLOSS
|
|
Total loss of precision. The result would have no significant digits;
|
|
e.g. <<sin(10e70)>>.
|
|
|
|
o PLOSS
|
|
Partial loss of precision.
|
|
o-
|
|
|
|
|
|
RETURNS
|
|
The library definition for <<matherr>> returns <<0>> in all cases.
|
|
|
|
You can change the calling function's result from a customized <<matherr>>
|
|
by modifying <<e->retval>>, which propagates backs to the caller.
|
|
|
|
If <<matherr>> returns <<0>> (indicating that it was not able to resolve
|
|
the error) the caller sets <<errno>> to an appropriate value, and prints
|
|
an error message.
|
|
|
|
PORTABILITY
|
|
<<matherr>> is not ANSI C.
|
|
*/
|
|
|
|
#include "fdlibm.h"
|
|
|
|
#ifdef __STDC__
|
|
int matherr(struct exception *x)
|
|
#else
|
|
int matherr(x)
|
|
struct exception *x;
|
|
#endif
|
|
{
|
|
int n=0;
|
|
if(x->arg1!=x->arg1) return 0;
|
|
return n;
|
|
}
|