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May 2008
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2008.05.26 15:22 "Re: beta2 release - lfind() problem on Win64", by Frank Warmerdam
Edward Lam wrote: > Hi, > > In trying to compile libtiff 4.0 beta 2 on Win64 with MSVC 8, I've > encountered the following warning which I think needs fixing: > > tif_dirinfo.c(508) : warning C4133: 'function' : incompatible types - > from 'size_t *' to 'unsigned int *' > > The problem is that the call to lfind() on Win64 is redirected to > _lfind() from search.h. For its 3rd argument, it hasn't been updated to > size_t * (pointer to 64-bits) and still uses unsigned int * (pointer to > 32-bits). I'm not quite sure what the best solution is at this time. On > the one hand, there's a comment that says we should use a binary search. > If we did use bsearch(), then it will fix the problem since bsearch() on > VC8 has been updated to use size_t (unlike _lfind). On the other hand, > I'm not convinced that the array it's trying to search in is sorted. > Well, I haven't actually looked but I assume it isn't sorted since it > would have been just as easy to call bsearch() instead of lfind(). > > Any thoughts? Edward, The field list is in sorted by key id, not name. It is a scary practice, but passing a size_t * in place of an int * should work on little endian machines since it just means the function will only use the lower order 4 bytes of the value. So, I'm inclined to take no action on this and leave the warning as a clue to a questionable practice. Frankly I hate using stuff like lfind() and bsearch() since it is amazing how varied the actual implementations and interfaces can be. I have created a bugzilla ticket to track this issue: http://bugzilla.maptools.org/show_bug.cgi?id=1889 Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | President OSGeo, http://osgeo.org