select_ents memory question

[bryan314]

Does anybody know if when using the eptrs and num_eptrs parameters in select_ents is the user responsible for freeing up the memory or does Mastercam clean it up later by itself?

 

Bryan

[markov]

While I have not used the function, I would say it simply returns pointers to elements from Mastercam's own database and no explicit freeing is expected from the caller.

 

But the function is either under-documented or dangerous. How does it know how big is your array it is supposed to fill? I think that *num_eptrs should be prefilled with the array size before the call, and the function will update it to reflect the number of elements store. That was the "under-documented" scenario from the above. The worse scenario is that it just stores as many entity pointers as needed, and you better provide a humongous array if you want to be safe!

[Roger Martin from CNC Software]

Bryan,

 

It’s been awhile since we’ve heard from you!

 

quote:

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Does anybody know if when using the eptrs and num_eptrs parameters in select_ents is the user responsible for freeing up the memory or does Mastercam clean it up later by itself?

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eptrs -- you do want to free.

 

if (eptrs != NULL) { free(eptrs); }

 

num_eptrs -- is just an int, so there would be no need to do a free on it.

 

Markov,

quote:

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I think that *num_eptrs should be prefilled with the array size before the call, and the function will update it to reflect the number of elements store.

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What would be the purpose of this?!?

“Prefilling” the count of something that you have no idea how many will be found would just be a unnecessary step.

[markov]

My bad, I did not see the double pointer there! I thought the array was supposed to be provided by the caller (along with its size to limit the number of stored entities). If the function allocates the array as needed, that is a completely different story.

[bryan314]

Hi Roger,

 

I've been hiding under a rock for awhile. Buried under a lot of other projects. I'm trying to get back to some chook bugs, upgrades, new chook requests here at the shop.

 

Thanks for the info. It just occurred to me while using the function there wasn't explicit "you need to clean this up yourself" comment in the doc and I was afraid of a memory leak. Or worse freeing it myself only to have MC do it later and crash.

 

Bryan