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1 point by lacker 6075 days ago | link | parent

What are these mzscheme functions you are referring to? I was just using a table keyed on thread for threadlocal storage. (Do I need to wrap table access in an atomic-invoke, by the way?)

I wish scheme documentation was more googleable. It's the opposite of javascript, in which you can find 100 ways to do anything, but they are all terribly ugly.



2 points by drcode 6075 days ago | link

http://download.plt-scheme.org/doc/mzscheme/mzscheme-Z-H-7.h...

Actually, how did you manage to key on thread? I couldn't figure out how to do this myself, since there isn't a "thread id" or anything that would work as a key...

I would assume (but don't know for sure) that arc tables are thread-safe- I would think you didn't need to worry about atomicity, here...

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1 point by lacker 6075 days ago | link

Thanks for the pointer. Looks like tables are indeed threadsafe. From your link -

"The hash-table-put! procedure is not atomic, but the table is protected by a lock."

As far as threadlocal goes... new-thread returns the thread descriptor and you can use that directly as a hash key.

  arc> (= a (table))
  #hash()
  arc> (= (a (new-thread (fn () (sleep 10)))) 5)
  5
  arc> a
  #hash((#<thread> . 5))
This is inconvenient by itself since in arc you can't access the current thread descriptor without some trickery. It seemed easiest to expose mzscheme's current-thread. I imagine that will have to end up in arc eventually.

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