Jeff Squyres wrote: > On Dec 16, 2009, at 3:35 PM, Jeff Squyres wrote: > > >> While preparing to SVN commit, I made the default for HG checkouts to >> compile with debug and picky modes. I now see a TRUCKLOAD of >> signed/unsigned comparison warnings. I'll look into these right now... >> > > A bunch of them were fairly straightforward "using int and unsigned together" > cases that were easy to fix. But some of them are less clear -- comparing > what should be unsigned values with -1. This makes me believe that -1 is > being used as a sentinel value in some places -- e.g., in > hwloc_obj_t->os_index. It's a "signed" field, but many of the comparisons > that are made to it are from "unsigned" variables. And at least in one or > two places, it is compared against -1. >
os_index == -1 means that it is unknown (or does not mean anything or whatever). > Which should be fixed -- make the .os_index field be unsigned (and either > have another boolean indicating whether the .os_index value is valid or not, > or having a sentinel value for invalid (perhaps ((unsigned) -1)?), or make > all the comparison variables be unsigned? > (unsigned) -1 is fine with me. Brice
