Writing EngExtCpp Extensions

The EngExtCpp extension library can include any standard C++ code. It can also include the C++ interfaces that appear in the engextcpp.h and dbgeng.h header files, in addition to the C functions that appear in the wdbgexts.h header file. Both dbgeng.h and wdbgexts.h are included from engextcpp.h.

For a full list of interfaces in dbgeng.h that can be used in an extension command, see Debugger Engine Reference.

For a full list of functions in wdbgexts.h that can be used in an extension command, see WdbgExts Functions. A number of these functions appear in 32-bit versions and 64-bit versions. Typically, the 64-bit versions end in "64" and the 32-bit versions have no numerical ending -- for example, ReadIoSpace64 and ReadIoSpace. When calling a wdbgexts.h function from a DbgEng extension, you should always use the function name ending in "64". This is because the debugger engine always uses 64-bit pointers internally, regardless of the target platform. When including wdbgexts.h, engextcpp.h selects the 64-bit version of the API. The ExtensionApis global variable used by the WDbgExts API is automatically initialized on entry to a EngExtCpp method and cleared on exit.

When an EngExtCpp extension is used with remote DbgEng interfaces, the WDbgExts interfaces will not be available and the ExtensionApis structure can be zeroed. If an EngExtCpp extension is expected to function in such an environment, it should avoid using the WDbgExts API.

Note   You must not attempt to call any DbgHelp or ImageHlp routines from any debugger extension. Calling these routines is not supported and may cause a variety of problems.