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pythondelphibokehc-api

loading bokeh into embedded python dll crashes

python (3.7.3) is embedded into a an executable via the C-API. When a Python Script is loaded with function PyImport_Import() and the script contains a bokeh import, i.e. from bokeh.plotting import figure the loading process ends prematurely with a floating point exception.

The executable is written in Delphi, but its python API is almost identical to the original C-API. I've loaded many other modules without any problems. bokeh is the first one that cannot be loaded.

The calling Delphi program, with the python dll already loaded into the exe process

  // module name as PPyObject
  pPyName := delpy.PyString_FromString(PAnsiChar(AnsiString(module)));
  // import module
  pPyModule := delpy.PyImport_Import(pPyName);

and the python script

import ptvsd
import pandas as pd
from bokeh.plotting import figure

def main_fnc():
    ptvsd.enable_attach(address=('localhost', 5678), redirect_output=True)
    ptvsd.wait_for_attach()
    breakpoint()
    print('Hello World!')

The following event log lists the dlls loaded into the process, showing only the last entries which - judged by their naming - are related to graphics functions. And finally the thrown error.

Loading Module: spline.cp37-win32.pyd. Without Debug-Infos. Base address: $2BD70000. Process XYZ.exe (8512)
Loading Module: _nd_image.cp37-win32.pyd. Without Debug-Infos. Base address: $2BDD0000. Process XYZ.exe (8512)
Loading Module: _ni_label.cp37-win32.pyd. Without Debug-Infos. Base address: $2BE00000. Process XYZ.exe (8512)
Loading Module: _spectral.cp37-win32.pyd. Without Debug-Infos. Base address: $2BE90000. Process XYZ.exe (8512)
Loading Module: _peak_finding_utils.cp37-win32.pyd. Without Debug-Infos. Base address: $2BEB0000. Process XYZ.exe (8512)
Loading Module: _hamilton_filter.cp37-win32.pyd. Without Debug-Infos. Base address: $2BFB0000. Process XYZ.exe (8512)
Loading Module: _kim_smoother.cp37-win32.pyd. Without Debug-Infos. Base address: $2BFF0000. Process XYZ.exe (8512)
Loading Module: linbin.cp37-win32.pyd. Without Debug-Infos. Base address: $2C030000. Process XYZ.exe (8512)
Loading Module: _smoothers_lowess.cp37-win32.pyd. Without Debug-Infos. Base address: $2C050000. Process XYZ.exe (8512)
Loading Module: _contour.cp37-win32.pyd. Without Debug-Infos. Base address: $2C280000. Process XYZ.exe (8512)
Loading Module: ft2font.cp37-win32.pyd. Without Debug-Infos. Base address: $2C2B0000. Process XYZ.exe (8512)
Loading Module: _png.cp37-win32.pyd. Without Debug-Infos. Base address: $2C450000. Process XYZ.exe (8512)
Loading Module: kiwisolver.cp37-win32.pyd. Without Debug-Infos. Base address: $2C4D0000. Process XYZ.exe (8512)
Loading Module: _image.cp37-win32.pyd. Without Debug-Infos. Base address: $2C580000. Process XYZ.exe (8512)
Loading Module: _tri.cp37-win32.pyd. Without Debug-Infos. Base address: $2C680000. Process XYZ.exe (8512)
Loading Module: _qhull.cp37-win32.pyd. Without Debug-Infos. Base address: $2C6B0000. Process XYZ.exe (8512)
First Chance Exception at $20762F54. Exception-Class $C0000090 with Message 'floating point invalid operation at 0x20762f54'. Process XYZ.exe (8512)
Solution

  • This usually happens when using external libraries. Calling SetExceptionMask to mask floating point exceptions might help in such cases.