Hello, I have written a C-extension for python that uses arrays from python, does calculations on them and returns a result on that. I have now also added the possibility to provide numpy arrays. However this is not a requirement. Python arrays (lists) are still allowed also. I check in the C-code which kind of arrays are provided. That all works ok, but I have one problem. In the initialisation function for the extension I call import_array to initialise the numpy library. The problem is if numpy is not installed on the system, that this call generates a message and an error and the rest of the routine is aborted. Via the source code of numpy I discovered that import_array is in fact a macro that calls _import_array and checks its return value to give the message. But even it I call _import_array myself and check for the return code, after the initialisation routine has finished I still get the message 'No module named numpy.core.multiarray'. How can I test if numpy is installed on the system from the extension so that I do not active the numpy functionality and that it is still able to use my extension, but then without numpy support? I have searched in the manual and documentation, searched in google, but I do not find an answer on that question.