On 2011-12-03 09:01-0000 Andrew Ross wrote: > > I have just committed a fairly large update to change the 2d arrays in > our API from const PLFLT ** to const PLFLT * const *. Gcc warns about > the use of const PLFLT ** because it only guarantees that the data is > constant not the array of pointers to the data. It is therefore trivial > to change the data by changing the pointers which is not what is > intended. Both the pointer array and the data need to be marked const. > > This is quite intrusive, but it seems to work ok for me. Please check. > It is strictly an API change however existing code should still > compile fine (possibly with warnings depending on the gcc settings). > > This does not remove all warnings - just shifts them (more later). It > does however make the API and the examples clean which I think is > more important for users. > > The const PLFLT * const * is a bit unwieldy however, so I propose > making a new typedef (something like PLFLT_2D_CONST) to tidy up > the code.
Assuming PLFLT is #defined like we have done, is "PLFLT * const *" something all c99-compliant compilers should understand or is that just a gcc extension? Even if the answer to that question is all c99-compliant compilers should understand it, it is possible their c99 implementations are buggy. Therefore, I think using a PLFLT_2D_CONST typedef (which we could #define differently for any major non-compliant compilers) might be a good idea from cross-platform point of view as well. For what it is worth, revision 12095 passes a limited test (just test_noninteractive in the build tree) on my Debian stable platform (gcc (Debian 4.4.5-8) 4.4.5). Furthermore, for that test using CXXFLAGS=-O3 -fvisibility=hidden CFLAGS=-O3 -fvisibility=hidden FFLAGS=-O3 there were no compiler warnings at all. That good result surprised me because there used to be tonnes of Java warnings and a sprinkling of C warnings. I don't know whether the Java warnings disappeared due to your efforts, but in any case we have come a long way in getting our code cleaned up thanks to your much appreciated efforts. 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 __________________________ ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
