The arguments to most CodeView commands are expressions. A source-level expression is a reference to a variable or a function call or one or more operations involving constants, variables, addresses, or function calls. A physical location is a register, a memory address or range, or a source-code line number that CodeView maps to an address.
To interpret expressions while maintaining its own programming language independence, CodeView uses dynamic-link libraries (DLLs) to look up symbols, parse, and evaluate expressions. These DLLs are called “expression evaluators.” This release of CodeView has two expression evaluators—one for source-level expressions in Microsoft and ANSI C and the other that handles C++. If you do not specify an expression evaluator, CodeView uses the C++ expression evaluator by default.
The C and C++ expression evaluators recognize most C operators and provide additional debugging operators that are not part of the languages. The C++ expression evaluator places certain restrictions on C++ expressions. Although there is no expression evaluator for the Microsoft Macro Assembler (MASM), the C and C++ expression evaluators support operators that simulate essential assembly-language operations. You use one of these expression evaluators when debugging MASM code.