To Hazen and Phil: Here is important additional information concerning the return code method of implementing an error report system that should make that method very much easier to maintain and test.
Phil originally expressed concern about the amount of developer time it would take to implement AND maintain propagation of return codes through all relevant caller paths, and he also proved my proposed method of testing potentially would not cover all caller paths. That combined with the degree of complexity in the caller paths illustrated by the doxygen results was also making me concerned about PLplot using the return code method of error reporting. However, I just discovered a method with gcc that would make the implementation and maintenance for that method a lot less of a burden. That method is as follows (see discussion in <http://stackoverflow.com/questions/2042780/how-to-raise-warning-if-return-value-is-disregarded-gcc-or-static-code-check> where the focus is on C++, but the method also works for C): The method uses the 'warn_unused_result' gcc attribute. A complication is that we already use the 'visibility( "default" )' attribute for some gcc cases in include/pldll.h(.in), and combinations of attributes must be done with a special attribute list syntax. So the bottom line is both the 'warn_unused_result' and 'visibility( "default" )' attributes would have to be combined appropriately in include/pldll.h(.in) to form the various PLDLLIMPEXP results there. And that file would likely also be the best place to implement the following #if defined ( __GNUC__ ) #define PL_WARN_UNUSED __attribute__((warn_unused_result)) #else #define PL_WARN_UNUSED #endif (Note that the PL_WARN_UNUSED macro would be needed for all functions (e.g., static ones) that don't have some form of PLDLLIMPEXP already deployed in the PLplot headers.) So, for example, a static function would be declared as static PLINT PL_WARN_UNUSED pl<function> Anyhow, assuming all this 'warn_unused_result' attribute infrastructure had been set up, then gcc should warn whenever an attempt is made by C/C++ code that calls a PLplot function to ignore the return code set by that function. So this gcc 'warn_unused_result' attribute would be an enormous help in finding and especially testing and maintaining all caller paths that are relevant to return code propagation. Anyhow, because of this (very) recent discovery I am once again confident of going ahead with an implementation of the return code method of error reporting (including even memory allocation issues since the cost of those has suddenly gone down) early in the next release cyle, and it appears Hazen is ready to help with that implementation as well. At the same time I have nothing against the alternative setjmp/longjmp C exception handling error reporting mechanism favored by Phil except that I don't completely understand it. But I would be willing to follow where Phil actively leads on that so let's hear from Phil about whether his current time constraints allow him to actively lead (i.e., doing some active coding and testing rather than making suggestions from the side) such a development before we make the final decision about which error reporting mechanism to use. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
