DEVNOTES.md

Development Notes

pyrtaudio crash (in archive)

• Using the following env vars to reproduce

$ PYTHONMALLOC=debug PYTHONTRACEMALLOC=1 python3 test_rtaudio_min.py

RtAudio Version 6.0.1
RtAudio_new: start.
RtAudio_new: api==NULL.
RtAudio_new: end.
RtAudio_init.
RtAudio_dealloc: start.
RtAudio_dealloc: self->dac
RtAudio_dealloc: pre: delete self->dac
RtAudio_dealloc: post: delete self->dac
RtAudio_dealloc: pre: Py_TYPE(self)->tp_free((PyObject*)self)
Debug memory block at address p=0x102d10440: API 'o'
    8 bytes originally requested
    The 7 pad bytes at p-7 are FORBIDDENBYTE, as expected.
    The 8 pad bytes at tail=0x102d10448 are not all FORBIDDENBYTE (0xfd):
        at tail+0: 0xa0 *** OUCH
        at tail+1: 0x60 *** OUCH
        at tail+2: 0xf9 *** OUCH
        at tail+3: 0x02 *** OUCH
        at tail+4: 0x01 *** OUCH
        at tail+5: 0x00 *** OUCH
        at tail+6: 0x00 *** OUCH
        at tail+7: 0x00 *** OUCH
    Data at p: 00 00 00 00 00 00 00 00

Memory block allocated at (most recent call first):
  File "/Users/sa/projects/python-rtaudio/build/test_rtaudio_min.py", line 3

Fatal Python error: _PyMem_DebugRawFree: bad trailing pad byte
Python runtime state: finalizing (tstate=0x00000001034bfd28)

Current thread 0x00007ff8562ab700 (most recent call first):
  <no Python frame>
Abort trap: 6

• trying again with with debug python

$ cd /Python-3.11.7
$ mkdir debug && cd debug
$ ../configure --with-pydebug --prefix=$HOME/projects/python-rtaudio/python
$ make install EXTRA_CFLAGS="-DPy_DEBUG"

debug python

• https://pythondev.readthedocs.io/debug_tools.html

type extension

• https://pythoncapi.readthedocs.io/type_object.html

• https://github.com/python/cpython/blob/main/Modules/zlibmodule.c

• https://geghamjivanyan.medium.com/c-c-extension-for-python-f68444dab472

Handling Thread Safety

• https://docs.python.org/3/c-api/init.html#thread-state-and-the-global-interpreter-lock

• https://docs.python.org/3/extending/newtypes_tutorial.html

• https://pythonextensionpatterns.readthedocs.io/en/latest/thread_safety.html

• https://github.com/paulross/skiplist

• https://opensource.com/article/17/4/grok-gil

Handling std::function

cython can't handle std::function directly, here are some links to workarounds:

• https://stackoverflow.com/questions/45943940/cython-stdfunction-callbacks-with-custom-parameter-types

• https://stackoverflow.com/questions/73083770/how-to-wrap-a-stdfunction-using-cython-for-python-usage

• https://stackoverflow.com/questions/39044063/pass-a-closure-from-cython-to-c/39052204#39052204

• https://github.com/hildensia/py_c_py

• https://stackoverflow.com/questions/21242160/how-to-build-a-cython-wrapper-for-c-function-with-stl-list-parameter