This is not really a MinGW problem, but MinGW does diverge from other compilers and it caused Firefox to crash.
MinGW defines a lot of I64[foo] format specifiers in inttypes.h. clang and clang-cl don't use I64[foo] they use ll[foo]. (I64[foo] is valid according to Microsoft. MinGW mentions "MS runtime does not yet understand C9x standard "ll"" but at some point they started supporting ll[foo]. And as I mentioned, that's what clang[-cl] uses. Mozilla has our own implementation of printf that does the format specifier parsing. We don't support I64[foo]. So using it caused data corruption and general bad behavior. Switching to ll[foo] fixed it. I have a patch here: https://hg.mozilla.org/try/raw-file/eaae7782a1dd/build/build-clang/mingw-int.patch (Try run for Firefox is here if anyone is interested: https://treeherder.mozilla.org/#/jobs?repo=try&revision=5db7504d12cf2e5181f2fcd46e09df37e0e80159&selectedJob=208082989 ) It may be desirable to take this patch, even though I64[foo] is valid, just because ll[foo] is much more common and it will unify behavior across compilers. (It would also be helpful for me; but we can support local patches to MinGW if you don't want to upstream this.) I64[foo] -> ll[foo] is not the only difference. The following illustrates other differences: https://ritter.vg/misc/transient/format-specifiers-diff.html -tom _______________________________________________ Mingw-w64-public mailing list Mingw-w64-public@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
