ArcGIS Engine Developer Guide

VISUAL C++
COM coclass header files in VC7 contain much less ATL code than at VC6. As
IDL is generated from attributes, there is typically no .idl file present in COM
projects as before, and the .idl file is generated at compile time.
Build configurations—There are only two default build configurations in VC7;
these are ANSI Debug- and Release-based builds. As ArcGIS is only available on
Unicode platforms, it is recommended to change these by modifying the project
properties. The general project properties page has an option for Character Set.
Change this from Use Multi-Byte Character Set to Use Unicode Character Set.
Character conversion macros—The character conversion macros
(USES_CONVERSION, W2A, W2CT, and so forth) have improved alternative
versions. These no longer allocate space on the stack, so they can be used in loops
without running out of stack space. The USES_CONVERSION macro is also no
longer required. These macros are now implemented as classes and begin with a
“C”—for example, CW2A, CW2CT.
Safe array support—This is available with CComSafeArray and
CComSafeArrayBound classes.
Module level global—The module-level global CComModule _module has
been split into a number of related classes, for example, CAtlComModule and
CAtlWinModule. To retrieve the resource module instance, use the following
code: _AtlBaseModule.GetResourceInstance();
String support—General variable length string support is now available through
CString in ATL. This is defined in the header files atlstr.h and cstringt.h. If ATL
is combined with MFC, this defaults to MFC’s CString implementation.
Filepath handling—A collection of related functions for processing the components
of filepaths is available through the CPath class defined in atlpath.h.
ATLServer—This is a new selection of ATL classes designed for writing Web
applications, XML Web services, and other server applications.
#import issues—When using #import, a few modifications are required. For
example, the #import of esriSystem requires an exclude or rename of GetObject,
and the #import of esriGeometry requires an exclude or rename of ISegment.
ATL REFERENCES
The Microsoft Developer Network provides a wealth of documentation, articles,
and samples that are installed with Visual Studio products. ATL reference documentation
for Visual Studio version 6 is under:
MSDN Library - October 2001 / Visual Tools and Languages / Visual Studio 6.0
Documentation / Visual C++ Documentation / Reference / Active Template Library
Additional documentation is also available on the MSDN Web site at
http://www.msdn.microsoft.com
You may also find the following books to be useful:
Grimes, Richard. ATL COM Programmer’s Reference. Chicago: Wrox Press Inc.,
1988.
Grimes, Richard. Professional ATL COM Programming. Chicago: Wrox Press Inc.,
1988.
Chapter 4 • Developer environments • 109