From 31c7b24aa5f57fbe8258c9e9845c8d630af4aec1 Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Fri, 1 Apr 2016 23:55:25 +0200 Subject: Silence MSVC warnings when using certain std algorithms The MSVC STL warns when passing naked pointers as non-bounded iterators to algorithms such as std::equal and std::copy, in an attempt to inform users that the range specified by that iterator has an implicit minimum size that the caller of the algorithm must ensure is met: warning C4996: 'std::_Equal1': Function call with parameters that may be unsafe - \ this call relies on the caller to check that the passed values are correct. To \ disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to \ use Visual C++ 'Checked Iterators' When building Qt, as well as when building user projects with qmake (cf. 0a76b6bc7f98900ea884cd10ccca1a332e5bdba5), we globally disable this warning (with -D_SCL_SECURE_NO_WARNINGS), but since we started using STL algorithms in public headers (e.g. in qvector.h), users get this warning in their own projects now, unless they, too, define said macro. But such a requirement is against the Qt policy to have headers that are warning-free as much as possible. The suggested way of fixing this warning is to wrap the naked pointer in a stdext::unchecked_array_iterator before passing it to the algorithm, cf. examples in https://msdn.microsoft.com/en-us/library/ttcz0bys%28v=vs.120%29.aspx or, together with the capacity-made-explicit, in a stdext::checked_array_iterator. To avoid ifdefs for platforms that don't have these extensions (which, incidentally, for the unchecked case, includes MSVC 2012), wrap the calls in macros. The end game here is to drop -D_SCL_SECURE_NO_WARNINGS, at least for public headers, even though this commit also adds the wrapper to implementation and private header files. An alternative to the wrapper would have been the version of std::equal that takes four iterators. However, that is a C++14 library feature, while this version of Qt still needs to compile with a C++98 compiler, and, more importantly, there isn't, and never will be, a corresponding 4-iterator version of std::copy. Task-number: QTBUG-47948 Done-with: Stephen Kelly Change-Id: I1bbab257fb5f1c5042939c382a412b596112ff26 Reviewed-by: Stephen Kelly --- src/plugins/platforms/windows/qwindowsinputcontext.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/plugins/platforms/windows/qwindowsinputcontext.cpp') diff --git a/src/plugins/platforms/windows/qwindowsinputcontext.cpp b/src/plugins/platforms/windows/qwindowsinputcontext.cpp index 1faa00d095..4d4be3d858 100644 --- a/src/plugins/platforms/windows/qwindowsinputcontext.cpp +++ b/src/plugins/platforms/windows/qwindowsinputcontext.cpp @@ -650,7 +650,7 @@ int QWindowsInputContext::reconvertString(RECONVERTSTRING *reconv) reconv->dwTargetStrOffset = reconv->dwCompStrOffset; ushort *pastReconv = reinterpret_cast(reconv + 1); std::copy(surroundingText.utf16(), surroundingText.utf16() + surroundingText.size(), - pastReconv); + QT_MAKE_UNCHECKED_ARRAY_ITERATOR(pastReconv)); return memSize; } -- cgit v1.2.3