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7640 :: Wrapping C Function Pointer Question

• hankas (orginal) [2021-03-16T08:27:56+01:00] view original

  Hi,

  I am new to Nim, and I am still learning. How do you wrap the following C function pointer in Nim?

  int (*callback)(void*,int,char**,char**)
  Run

  I tried to do the followings but it does not seem to work.

  type
    Callback = proc(customArg: pointer, columnCount: cint, values: cstringArray, columns: cstringArray): cint
  Run

  Any help?

  Thanks.

  Henry

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• ElegantBeef (orginal) [2021-03-16T10:12:02+01:00] view original

  You may also need {.cDecl.} or {.noConv.} on the type to make it interoppable with the C code.

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• marcomq (orginal) [2021-03-16T13:02:45+01:00] view original

  As summary, this could be:

  type Callback =
    proc(customArg: pointer, columnCount: cint, values, columns: cstringArray): cint {.cdecl.}
  Run

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• hankas (orginal) [2021-03-17T08:13:11+01:00] view original

  Got it. Thanks. What does the noconv pragma do?

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• ElegantBeef (orginal) [2021-03-17T09:05:01+01:00] view original

  You can read about the conventions here Just scroll down a tad bit.

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• hankas (orginal) [2021-03-17T09:05:43+01:00] view original

  Ok. Thanks.

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