There are rare but real cases when a nopython-mode function needs to callback into the Python interpreter to invoke code that cannot be compiled by Numba. Such cases include:
- logging progress for long running JIT'ed functions;
- use data structures that are not currently supported by Numba;
- debugging inside JIT'ed code using the Python debugger.
When Numba callbacks into the Python interpreter, the following has to happen:
- acquire the GIL;
- convert values in native representation back into Python objects;
- call-back into the Python interpreter;
- convert returned values from the Python-code into native representation;
- release the GIL.
These steps can be expensive. Users should not rely on the feature described here on performance-critical paths.
Warning
This feature can be easily mis-used. Users should first consider alternative approaches to achieve their intended goal before using this feature.
.. autofunction:: numba.objmode