ESP8266 Community Forum

- Fri Apr 17, 2015 12:26 pm #14841

Just remember to make everything local and even though an event has fired the reference to it is still in the handlers table, preventing GC, so doing an s:on("connection", nil) in update_factory() will dereference itself allowing GC, etc.

Moin Terry,

are you sure on this? I was under the impression that net_delete (the destructor) does free the connection ref
luaL_unref(L, LUA_REGISTRYINDEX, nud->cb_connect_ref);
on s:close and that this is even a problem because the registered disconnect handler may access freed memory.

Carsten

Get your modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Fri Apr 17, 2015 12:41 pm #14845

You're possibly trying to concatenate a nil variable. As a test, try replacing:..

How about:

Code: Select all> for i,v in ipairs ({1,3,nil, 4}) do print (i,v) end
1   1
2   3

ipairs() stops at the first nil value so neither i nor v will be nil. Yes, you need to be aware of the possibility of nil values in some cases but not this one.

Please see my Developer FAQ for Q&A on nodeMCU Lua before asking a question here that's already been answered. This and the other official documentation should be your first reference for developing Lua Apps

- Fri Apr 17, 2015 12:46 pm #14846

are you sure on this? I was under the impression that net_delete (the destructor) does free the connection ref
luaL_unref(L, LUA_REGISTRYINDEX, nud->cb_connect_ref);
on s:close and that this is even a problem because the registered disconnect handler may access freed memory.

Carsten, you might be right in the case of this DTOR, but I came across this issue with tmr alarms where setting the value to nil does free up extra memory.

Please see my Developer FAQ for Q&A on nodeMCU Lua before asking a question here that's already been answered. This and the other official documentation should be your first reference for developing Lua Apps

- Wed Apr 29, 2015 12:23 pm #16033 Thank you all for the information. I wound up using string.format in my code instead of concatenation, I suspect auto-typecast is expensive.