Data Types for Visual Basic

Visual Basic uses a different set of calling and programming conventions than C and C++ use. Different structure and parameter definitions support the Visual Basic representation of strings and of structures, which in Visual Basic are called types. The following list describes how programming Simple MAPI Visual Basic applications differs from programming Simple MAPI C and C++ applications:

• In C and C++, structures can contain pointers to other structures. Because the concept of a pointer is foreign to Visual Basic, extra function parameters are used instead of these complex structures.
• Because the Visual Basic MAPI functions are declared, it is not necessary to explicitly cast passed arguments using ByVal.
• An empty string in a string variable is equivalent to a NULL value.
• Arrays must be dynamically declared so that they are redimensioned when the Simple MAPI function is executed.
• Visual Basic manages memory, eliminating the need to call the MAPIFreeBuffer function.
• All structures used in the Visual Basic version of Simple MAPI are Visual Basic types rather than C-language structures.
• All strings used in the Visual Basic version of Simple MAPI are Visual Basic strings rather than C-language strings.

The following alphabetized entries contain documentation for the Visual Basic Data Types