6.1.7 Generating C prototypes from Fortran

The options -fc-prototypes can be used to write out C declatations and function prototypes for BIND(C) entities. The same can be done for writing out prototypes for external procedures using -fc-prototypes-external, see Interoperability Options.

Standard Fortran does not specify an interoperable type for C’s unsigned integer types. For interoperability with unsigned types, GNU Fortran provides unsigned integers, see Unsigned integers.