Preprocessor Statements

Preprocessor statements, with the exception of preprocessor procedures, are executed as they are encountered. Preprocessor procedures must be invoked in order to be executed. Preprocessor statements, except those in preprocessor procedures, begin with a percent symbol (%). Blanks, tabs, and returns may separate the percent symbol from the rest of the statement, except where indicated.

The preprocessor executes preprocessor statements and alters the input text accordingly. Preprocessor statements can cause parts of the input text to be altered in any of the following ways:

• Any identifier (and optional argument list) appearing in the input text can be changed to become an arbitrary string of text.
• If a conditional compilation is desired, the programmer can indicate which sections of the program are to be compiled and which discarded.
• Strings of text residing in different files can be incorporated into the source program.