Why is C used in many optimization libraries?

[jacobwilliams]

@Beliavsky

The FORTRAN 77 code could be converted to free source form with a tool and put in a module along with modern Fortran wrappers. The module can be declared PRIVATE with only the wrappers given the PUBLIC attribute, so that the FORTRAN code is inaccessible outside the module.

Oh I agree totally! That’s a fine approach. Then you have it in good shape for further modernizations if necessary.