### Preprocessor

To run only the preprocessor, specify /P with the icc command.

If you run only the preprocessor, you can use the preprocessor output (which has all the preprocessor directives executed, but no code compiled) to debug your program. For example, all macros are expanded, and the code for all files included by #include directives appears in your program.

Preprocessor directives, such as #include, allow you to include C or C++ code from another source file into yours, to define macros, and to expand macros.

By default, comments in the source code are not included in the preprocessor output. To preserve the comments, use the /Pc option.

For C programs, if you use // to begin your comments, you must also specify the /Ss option to include those comments in the preprocessor output.

Preprocessor Directives

Summary of Compiler Options
Summary of Compiler Options by Function