I would try Fortran-C interop. With something like
interface
function cublas_alloc(argument list) bind(C, name="the_binding_name")
defs of arguments
end function
end interface
the binding name can be upper case or lowercase, whatever you need, for example, bind(C,name="CUBLAS_ALLOC")
. No underscores will be appended to that.
The iso_c_binding
module might be also helpful.