Active Template Library

COM objects can also be created with Microsoft Foundation Classes (MFC), but this leads to larger binaries that require support DLLs.{{cite book | title = Visual C++ 6 Unleashed | edition = 1st | chapter = Active Documents | page = 733 | last = Williams | first = Mickey | year = 2000 | publisher = Sams | isbn = 978-0-672-31241-0 }} ATL, on the other hand, is a more lightweight alternative in situations where the graphical user interface parts of MFC are not required.Microsoft MSDN: [https://msdn.microsoft.com/en-us/library/bk8ytxz5.aspx Recommendations for Choosing Between ATL and MFC]

Older versions of ATL (ATL prior to version 7.1, pre-Visual Studio 2005) are incompatible with DEP because it places executable thunks in data heap.http://web.archive.org/web/20080130115007/http://blogs.msdn.com/michael_howard/archive/2008/01/29/new-nx-apis-added-to-windows-vista-sp1-windows-xp-sp3-and-windows-server-2008.aspxhttps://learn.microsoft.com/en-us/archive/blogs/michael_howard/new-nx-apis-added-to-windows-vista-sp1-windows-xp-sp3-and-windows-server-2008https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/

This problem can be mitigated with DEP-ATL thunk emulation with performance penalty.http://web.archive.org/web/20090123222148/http://support.microsoft.com/kb/948468https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-updateprocthreadattribute

In ATL version 7 (Visual Studio 2003), which directly succeeded version 3 (Visual Studio 6.0), a number of MFC classes like CString were made available in ATL, or more precisely moved to an ATLMFC common layer which is shared by both libraries. ATL version 7 also introduced attributes in C++ in an attempt to provide something similar to CLI attributes, however these have not been particularly successful, and have been deemphasized in ATL version 8 (Visual Studio 2005); the various wizards no longer generate them by default. Version 7 also introduced new string conversion classes.

On July 28, 2009, Microsoft released a patch to ATL to fix a bug that could allow ActiveX controls created using ATL to be vulnerable to a remote code execution security flaw.{{cite web|url=http://msdn.microsoft.com/en-us/visualc/ee309358.aspx |title=ATL Security Update |publisher= Microsoft|work = MSDN| date=2009-07-28 |access-date=2011-09-19}}

Since Visual Studio 2013 (ATL version 12), all ATL code is static, eliminating the DLL.http://web.archive.org/web/20130827013146/http://blogs.msdn.com/b/vcblog/archive/2013/08/20/atl-and-mfc-changes-and-fixes-in-visual-studio-2013.aspxhttps://devblogs.microsoft.com/cppblog/atl-and-mfc-changes-and-fixes-in-visual-studio-2013/

ATL version is defined by ATL_VER macros and can be queried via AtlGetVersion() function.https://learn.microsoft.com/en-us/cpp/atl/reference/atl-text-encoding-functions?view=msvc-170#atlgetversion

ATL includes many RAII classes to simplify management of COM types. The most commonly used classes include:

• CComPtrMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/ezzw7k98.aspx CComPtr Class] general-purpose smart-pointer,
• CComBSTRMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/zh7x9w3f.aspx CComBSTR Class] BSTR wrapper,
• CComVariantMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/ac97df2h.aspx CComVariant Class] VARIANT wrapper, and
• CComSafeArrayMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/3xzbsee8.aspx CComSafeArray Class] SAFEARRAY wrapper.

Although not formally part of ATL, Microsoft Visual C++ also includes additional C++ RAII classes to simplify management of COM types. These compiler COM support classes can be used as replacement for or in combination with ATL, and includes:

• _com_ptr_tMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/417w8b3b.aspx _com_ptr_t Class] smart-pointer that decorates the COM interface name with a "Ptr" suffix,
• _bstr_tMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/zthfhkd6.aspx _bstr_t Class] BSTR wrapper,
• _variant_tMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/x295h94e.aspx _variant_t Class] VARIANT wrapper, and
• _com_errorMicrosoft MSDN: [https://msdn.microsoft.com/en-us/library/0ye3k36s.aspx _com_error Class] HRESULT wrapper.

Note that as of Visual Studio 2012, the compiler COM support classes does not include a SAFEARRAY wrapper.

• ATL Server
• C++/CX
• OLE Automation
• Standard Template Library
• Windows Template Library
• Microsoft Windows SDK
• List of C++ template libraries

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• [https://msdn.microsoft.com/en-us/library/t9adwcde.aspx Official MSDN reference documentation]

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Category:C++ libraries

Template Library