Hi list, Iemguts has an object [canvasdelete] which, when you create it, goes in and adds a "delete" method for canvases. This allows you to send a "delete $1 $2 etc." message to a canvas, where "$1 $2 etc." are indices of objects you wish to delete from a particular canvas.
In the code I see this comment:
/* this will crash Pd if the object to be deleted is on the stack * workarounds: * - use a clock (see above) * - finally fix this in Pd */
- How do I use a clock? If the object no longer outputs in zero
logical time, does that make certain use cases impossible? (If not maybe that's the way to go.) 2) How would you finally fix this in Pd without using a clock?
-Jonathan
On 06/14/2014 08:13 PM, Jonathan Wilkes via Pd-list wrote:
Hi list, Iemguts has an object [canvasdelete] which, when you create it, goes in and adds a "delete" method for canvases. This allows you to send a "delete $1 $2 etc." message to a canvas, where "$1 $2 etc." are indices of objects you wish to delete from a particular canvas.
In the code I see this comment:
/* this will crash Pd if the object to be deleted is on the stack
- workarounds:
- use a clock (see above)
- finally fix this in Pd
*/
- How do I use a clock? If the object no longer outputs in zero
the problem is, that if an object delete's itself, it will delete a context that is referenced later when unwinding the stack.
logical time, does that make certain use cases impossible? (If not maybe that's the way to go.)
[canvasdelete] itself uses a clock.
- How would you finally fix this in Pd without using a clock?
basically we have to defer deletion of a context until it is no longer used. afaict, there are two ways:
- tell Pd to only delete an object once it is safe to do so. this is
basically the clock_delay() method used in [canvasdelete].
- use refcounting, so know when nobody is using the object's context
anymore.
gfasdrm IOhannes
On 06/14/2014 02:33 PM, IOhannes m zmölnig via Pd-list wrote:
On 06/14/2014 08:13 PM, Jonathan Wilkes via Pd-list wrote:
Hi list, Iemguts has an object [canvasdelete] which, when you create it, goes in and adds a "delete" method for canvases. This allows you to send a "delete $1 $2 etc." message to a canvas, where "$1 $2 etc." are indices of objects you wish to delete from a particular canvas.
In the code I see this comment:
/* this will crash Pd if the object to be deleted is on the stack * workarounds: * - use a clock (see above) * - finally fix this in Pd */
- How do I use a clock? If the object no longer outputs in zero
the problem is, that if an object delete's itself, it will delete a context that is referenced later when unwinding the stack.
Thanks.
Where is the stack-maintenance code for Pd located?
-Jonathan
On 06/15/2014 11:49 AM, IOhannes m zmölnig via Pd-list wrote:
On 06/14/2014 09:50 PM, Jonathan Wilkes via Pd-list wrote:
Where is the stack-maintenance code for Pd located?
on the stack? (like: automatically, as in other C-implemented binaries)
Oh. I thought Pd had some specific code related to the stack, but I guess I was thinking of the pdfile-reading stuff in pd.c.
-Jonathan
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IOhannes m zmölnig via Pd-list -
Jonathan Wilkes via Pd-list