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11338 :: How to remove the N_LIB_PRIVATE from exported c code.

• Nlits (orginal) [2024-04-01T19:49:33+02:00] view original

  I am using the exportc pragma to attempt to export to c then WASM, but the function never appears in the WASM and is generated with N_LIB_PRIVATE in the c code. Is there anyway to remove this or am I getting the cause of my issue completely wrong? (I found in the c code only the functions without N_LIB_PRIVATE were exported in WASM)

  C Code:

  N_LIB_PRIVATE N_NIMCALL(NCSTRING, add_nfunc)(NCSTRING* nfuncsX60flatArgs__p0, NI nfuncsX60flatArgs__p0Len_0); // I am pretty sure N_NIMCALL does nothing as N_CDECL has the same error
  Run

  Nim Code

  proc add*(nfuncs`flatArgs: openArray[cstring]): cstring {.gcsafe, exportc: "add_nfunc".} =
    …
  Run

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• ElegantBeef (orginal) [2024-04-01T21:53:29+02:00] view original

  You should use exportc, dynlib to ensure a procedure is not dead code removed. Depending on your wasm compiler you may also want to use codegenDecl to add the correct annotation to your procedure.

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• Nlits (orginal) [2024-04-01T22:17:57+02:00] view original

  Should I use just exportc and dynlib or should I use cdecl as the docs say too?

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• Nlits (orginal) [2024-04-01T22:24:48+02:00] view original

  Successful: (with dynlib pragma)

  N_LIB_EXPORT N_CDECL(NCSTRING, add_nfunc)(NCSTRING* nfuncsX60flatArgs__p0, NI nfuncsX60flatArgs__p0Len_0);
  Run

  WAST:

  
   (export "add_nfunc" (func $52))
  Run

  👍

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• ElegantBeef (orginal) [2024-04-01T23:16:17+02:00] view original

  If you're sharing code with other languages the correct annotation is cdecl, exportc, dynlib though in many cases nimcall is compatible with cdecl

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• Nlits (orginal) [2024-04-01T23:25:21+02:00] view original

  Is there any reason why your wasm3 package is not on nimble? I was going to make my own wasm runtime wrapper, but now that I know one exists I don’t need to. As for the emcc keep alive thing, I will see if I need to use it. (I might)

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• ElegantBeef (orginal) [2024-04-02T01:31:32+02:00] view original

  I am generally of the view packages should only be on a package registry if they're of sufficient quality. Which means have tests, and documentation. Since Nimble is decentralized there is not much reason to add what I consider incomplete packages.

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• ringabout (orginal) [2024-04-02T04:57:20+02:00] view original

  Neat macros! Let me see whether I can make __attribute__((used))/EMSCRIPTEN_KEEPALIVE into nimbase.h

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• ringabout (orginal) [2024-04-02T08:29:06+02:00] view original

  See also https://github.com/nim-lang/Nim/pull/23469 => dynlib keeps exported functions alive in emscripten

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