Re: LuaJIT FFI callbacks (was Re: Calling lua functions from C when using luajit ffi.)

[James McKaskill <james@...>]

On Nov 14, 2011, at 19:30 , Duncan Cross wrote:
> 
> This is fantastic news! Thanks so much for your work, and thanks too
> to the anonymous sponsor.
> 
> One thing - I'm not certain this is related to the addition of
> callbacks, but I was just experimenting with Win32 calls and found
> that GetLastError() seems to return the wrong value (127,
> ERROR_PROC_NOT_FOUND) the first time it's called. This is a minimal
> test case:
> 
>  local ffi = require("ffi")
> 
>  ffi.cdef [[
>  uint32_t GetLastError();
>  void SetLastError(uint32_t code);
>  ]]
> 
>  ffi.C.SetLastError(0)
>  print(ffi.C.GetLastError()) -- 127
>  ffi.C.SetLastError(0)
>  print(ffi.C.GetLastError()) -- 0
> 
> (I'm explicitly setting the error here, but I discovered it because it
> was hiding a parameter error while I was experimenting with trying to
> call RegisterClassExA().)
> 
> -Duncan
> 

I would not suggest trying to get errors using Get/SetLastError as they will be invalidated by the vm. If you really want the error use ffi.errno().

-- James

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