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/* |
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* ==================================================== |
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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* |
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* Developed at SunPro, a Sun Microsystems, Inc. business. |
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* Permission to use, copy, modify, and distribute this |
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* software is freely granted, provided that this notice |
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* is preserved. |
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* ==================================================== |
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*/ |
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<>---modifiable math error handler |
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matherr |
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#include |
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int matherr(struct exception *<[e]>); |
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#include |
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int matherr(*<[e]>) |
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struct exception *<[e]>; |
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<> is called whenever a math library function generates an error. |
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You can replace <> by your own subroutine to customize |
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error treatment. The customized <> must return 0 if |
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it fails to resolve the error, and non-zero if the error is resolved. |
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and the value of <> is not modified. You can accomplish either |
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or both of these things in your own <> using the information |
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passed in the structure <<*<[e]>>>. |
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. struct exception { |
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. int type; |
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. char *name; |
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. double arg1, arg2, retval; |
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. int err; |
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. }; |
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o+ |
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o type |
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The type of mathematical error that occured; macros encoding error |
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types are also defined in `<>'. |
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a pointer to a null-terminated string holding the |
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name of the math library function where the error occurred. |
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The arguments which caused the error. |
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The error return value (what the calling function will return). |
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If set to be non-zero, this is the new value assigned to <>. |
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o- |
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errors as follows: |
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o DOMAIN |
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An argument was not in the domain of the function; e.g. <>. |
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The requested calculation would result in a singularity; e.g. <> |
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A calculation would produce a result too large to represent; e.g. |
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<>. |
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A calculation would produce a result too small to represent; e.g. |
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<>. |
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Total loss of precision. The result would have no significant digits; |
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e.g. <>. |
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Partial loss of precision. |
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o- |
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The library definition for <> returns <<0>> in all cases. |
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by modifying <retval>>, which propagates backs to the caller. |
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the error) the caller sets <> to an appropriate value, and prints |
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an error message. |
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<> is not ANSI C. |
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*/ |
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int matherr(struct exception *x) |
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#else |
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int matherr(x) |
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struct exception *x; |
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#endif |
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{ |
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int n=0; |
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if(x->arg1!=x->arg1) return 0; |
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return n; |
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} |
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