Access violation in mkl_set_interface_layer with Python 3

Using mkl_set_interface_layer from Python 3 on Windows 10 with the latest MKL installed gives an access violation. Specifically this code:

from ctypes import *
mkl = cdll.LoadLibrary('mkl_rt')
mkl.mkl_set_interface_layer(c_int(1))

produces this error:

OSError: exception: access violation reading 0x0000000000000001

Note using c_int(0) in place of c_int(1) gives an analogous error. Variables in the console are set using mklvars.bat (notably the PATH variables are set properly), and I have checked that several of the cblas_* functions are working. Is there some library I have to load, or specify a calling convention?

Thanks.