A Visual Basic 7.0 program consists of one or more separate source files. When a program is compiled, all of the source files are processed together. Thus, source files can depend on each other, possibly in a circular fashion without any forward-declaration mechanism.
A source file consists of an optional set of attributes, option directives and import directives, followed by a namespace body. The body of the source file functions as an implicit namespace declaration for the global namespace, meaning that all declarations at the top level of a source file are placed in the global namespace. The textual order in which declarations are made in the program text is generally of no significance, with some exceptions.