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10474 :: Disable GC-safety in Nim 2.0?

• Hobbyman (orginal) [2023-09-12T21:46:02+02:00] view original

  Is it true that gc-safety is compulsory in Nim 2.0 (I use Jester) a.o.t. recommended / warned in 1.x. At compiling in 2.0, I get:

  /home/thisuser/.choosenim/toolchains/nim-2.0.0/lib/pure/asyncmacro.nim(250, 31) Error: 'match (Async)' is not GC-safe as it calls 'showPage'

  showPage calls indeed a global variable. Must I remove all global vars to move to 2.0? In nim 1.6.14 the same issue is just a warning. It is a major rewrite to remove all globals.

  Is there a way to disable that stopping-error. Maybe a compiler-option or pragma? Or must I stay in 1.x if i dont want to remove the globals. Is it necessary to force users to reprogram their apps if they dont intend to implement multi-threading, or is there some other option? Or is it an ORC-thing?

  Thanks in advance.

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• choltreppe (orginal) [2023-09-12T21:53:01+02:00] view original

  you can use '{.gcsafe.}' block:

  {.gcsafe.}:
    ...
    # your code
    ...
  Run

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• Hobbyman (orginal) [2023-09-12T21:58:53+02:00] view original

  I will try that, thanks!

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• Yardanico (orginal) [2023-09-12T22:28:29+02:00] view original

  If your async app is single threaded you can also use this hammer approach: --threadAnalysis:off. It completely disables those checks, so be careful.

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• PMunch (orginal) [2023-09-12T22:47:41+02:00] view original

  Would --threads:off have the same effect?

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• Hobbyman (orginal) [2023-09-12T22:57:36+02:00] view original

  Thanks for all solutions!

  {.gcsafe.} must apparently be implemented per function..

  The app compiled with --threadAnalysis:off Crude but effective. Strangely enough with four threads now, but i am happy (for now) :-)

  --threads:off compiles with one thread...

  Then I can slowly clean it up. It is an older app; then i didnt know globals are not recommended...

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