These two examples demonstrate how a FORTRAN90 program can call a C function in a way that is "guaranteed" to work in other words, the procedure follows rules laid down by the FORTRAN standard, and does not depend on any special or peculiar features of the FORTRAN and C compilers used to compile the programs. -These two examples demonstrate how a FORTRAN90 program can call a C function in a way that is "guaranteed" to work　in other words, the procedure follows rules laid down by the FORTRAN standard, and does not depend on any special or peculiar features of the FORTRAN and C compilers used to compile the programs.