[GiNaC-devel] remove_dirac_ONE() and documentation patches

[Vladimir V. Kisil]

	Dear Alexey,

	I am attaching another iteration of the patch as suggested. The
  exception-free method is used internally for a better protection.

	Best wishes,
	Vladimir
-- 
Vladimir V. Kisil                 http://www.maths.leeds.ac.uk/~kisilv/
  Book:     Geometry of Mobius Transformations     http://goo.gl/EaG2Vu
  Software: Geometry of cycles          http://moebinv.sourceforge.net/
>>>>> On Mon, 20 May 2019 18:06:38 +0400, Alexey Sheplyakov <asheplyakov at yandex.ru> said:

    ASh> Hello,

    ASh> 20.05.2019, 02:29, "Vladimir V. Kisil"
    ASh> <kisilv at maths.leeds.ac.uk>:

    >>         Many thanks for the useful suggestions. I have revised my
    >> patch   in accordance with your first suggestion: both the old
    >> and the new   version are present. This patch is attached below.

    ASh> This version looks better, but

    >> +ex remove_dirac_ONE(const ex & e, bool *success, unsigned char
    >> rl = 0, unsigned options = 0); +

    ASh> it still subtly changes the meaning of

    ASh> remove_dirac_ONE(e, 0, 0);

    ASh> Before the patch it was remove_dirac_ONE(e, /* rl = */ 0, /*
    ASh> options = */ 0), and with patch it's remove_dirac_ONE(e, /*
    ASh> success = */ 0, /* rl = */ 0) which  

    ASh> 1) does not throw an exception on error 2) segfaults

    ASh> Please change the prototype (of the non-throwing function) to

    ASh> ex remove_dirac_ONE(const ex& e, bool& success, unsigned char
    ASh> rl = 0, unsigned options = 0);

    ASh> This way the compiler can pick the correct overload

    ASh> e = remove_dirac_ONE(e, 0, 0); // OK: remove_dirac_ONE(const
    ASh> ex&, unsigned char, unsigned) bool ok = false; e =
    ASh> remove_dirac_ONE(e, ok, 0, 0);


    >>   Regarding crashes of my application the situation was solved by
    >>   partial substitution: I was able to avoid crashes keeping the
    >> original   version of GiNaC. It was enough to replace calls to
    >> exception-free   version of remove_dirac_ONE to in my library
    >> only. Probably exceptions   work fine within one library but
    >> create crashes if passed between   different libraries.

    ASh> I don't quite understand how patching *just* remove_dirac_ONE
    ASh> could possibly avoid the cross-DLL exceptions problem. See,
    ASh> many (most?) GiNaC methods and functions use exceptions to
    ASh> report an error. For instance, pseries::power_const throws
    ASh> pole_error. Why this one is not a problem? What's special about
    ASh> remove_dirac_ONE?


    ASh> Best regards,      Alexey
    ASh> _______________________________________________ GiNaC-devel
    ASh> mailing list GiNaC-devel at ginac.de
    ASh> https://www.cebix.net/mailman/listinfo/ginac-devel
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