Re: Segmentation Fault in Creating NodeItems

[Paul E. Johnson]

Darren Schreiber wrote:
> 
> <x-rich>
> 
> When I build the Agent in the modelSwarm, I am having the Agent create a
> node for them on the canvas.  Using the following code:
> 
> -setNode: (id) aCanvas {
> 
>   agentNode = [OvalNodeItem createBegin: [self getZone]];
> 
>   [agentNode setCanvas: aCanvas];
> 
>   [agentNode setX: 50 Y: 50];
> 
>   [agentNode setString: (const char*) agentID];
> 
>   //[agentNode setTargetID: self];
> 
>   agentNode=[agentNode createEnd];
> 
>   return self;
> 
> }
> 
> It compiles fine, but I get the following error:
> 
> Program received signal SIGSEGV, Segmentation fault.
> 
> 0x41e53d in _i_NodeItem__createPaddedText (self=0x4964188, _cmd=0x4b91e8)
> 
>     at /src/Swarm/swarm/src/tkobjc/NodeItem.m:150
> 
> /src/Swarm/swarm/src/tkobjc/NodeItem.m:150: No such file or directory.
> 
> (gdb)
> 
> When I step through the problem using a break, the segmentation fault
> occurs at the line agentNode=[agentNode createEnd];

I think the problem is that you have some methods from the "using"
section inside your createBegin/End brackets.

Only commands that show in the docs in the creating phase can go between
those two.  Absolutely for certain you don't want setX:Y:, setString: in
there.  

Move those after createEnd and I bet it works OK

-- 
Paul E. Johnson                         email: address@hidden
Dept. of Political Science              http://lark.cc.ukans.edu/~pauljohn
University of Kansas                    Office: (785) 864-9086
Lawrence, Kansas 66045                  FAX: (785) 864-5700

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