I’m trying to test libpd out by merely having it read a patch with [osc~ 440] -> [dac~]

I’m currently doing:

pdengine = new pd::PdBase();
  
pdengine->init (/*NInChannels()*/ 0, 2, GetSampleRate());


patch = pdengine->openPatch("testpatches/sine.pd", ".");

// audio processing on
pdengine->computeAudio(true);

and so on.

The line:

patch = pdengine->openPatch("testpatches/sine.pd"".");

gives

Thread 1: EXC_BAD_ACCESS (code=1, address=0x28) on pdengine->openPatch()

the testpatches folder exists at “." and contains sine.pd.

What’s wrong?