hi,
whoever attempted closing /doc/5.reference/pointer.pd (is there anyone that curious?), would have probably noticed a strange behaviour:
- Closing the main patch with a data-subpatch window left open
(as it was loaded) crashes Pd.
- Closing data-subpatch window first, then closing the main patch
does not crash Pd.
After some digging I found that:
- In template_free() there is a relevant comment:
``figure out how to get rid of data having this template''. It is marked `LATER'.
- If a template is destroyed first -- before destruction of those
scalars that use this template -- and if the canvas holding those scalars has its window open, then Pd dies. The reason: freeing a visible canvas means calling vis-routines of all objects in this canvas -- scalar_vis() is called, while there is no template.
- Since what is deadly here is the scalar_getbasexy() call, Pd
dies quietly, with no error message printed. Adding an early check into scalar_vis() would work as a temporary safeguard:
float basex, basey;
- if (!glist) return; scalar_getbasexy(x, &basex, &basey); if (!glist) bug ("scalar_vis");
- This safeguard would not prevent scalar_free() from complaining
``scalar: couldn't find template'', but it is much lesser evil than crashing.
- This crash is yet another case of order dependence horror.
If data-canvas had been stored within pointer.pd file before tamplate-canvases, no crash would have occured.
Krzysztof