Performing OLE/COM-conforming conversion of data types

The OLE/COM protocol defines a set of valid conversions among Variant types. You can avoid having to hard-code these conversions in your own code if you use the set of low-level conversion functions provided by the COM-Automation API (Oleaut32.dll). f90VB includes a complete set of Fortran wrappers to these conversion functions. Note that these are direct wrappers; f90VB’s only intervention between the calls to these subroutines is to re-arrange the argument into a format suitable for use in Fortran. The list of these functions and their descriptions can be found in the f90VB Reference Manual.

Calling Fortran from Visual Basic and Visual Basic for Applications