Sun Studio 12 Update 1: Fortran User's Guide

3.4.156 –xpp={fpp|cpp}

Select source file preprocessor.

The default is -xpp=fpp.

The compilers use fpp(1) to preprocess .F, .F95, or .F03 source files. This preprocessor is appropriate for Fortran. Previous versions used the standard C preprocessor cpp. To select cpp, specify -xpp=cpp.