Re: ffi:make-pointer failed on mingw64 build

Thanks,

have tried uintptr_t, but ecl does not recognize it now .

also noticed you are working on function pointer.

I found this article is helpful,

Divergent 64-bit Integer Sizes Across Platforms: ILP64, LP64, and LLP64 
Explained

https://sqlpey.com/c++/divergent-64bit-integer-sizes/


On 6/22/2026 16:07, Daniel Kochmański wrote:
> Hello Yuguo,
>
> thanks for the report.
>
>> I'm testing a cl-opengl project.
>>
>> An make-pointer error raised when submit data to OpenGL using
>> gl:BufferData,.
>>
>> After some digging, I found it's caused by the function
>>
>> (defun make-pointer (addr type)
>>     (c-inline (type (size-of-foreign-type type) addr) (:object
>> :unsigned-long :unsigned-long) :object
>>               "ecl_make_foreign_data(#0, #1, (void*)#2)"
>>               :side-effects t
>>               :one-liner t))
>>
>> in src/ffi.lsp.
>>
>>
>> the native type of 3rd argument is specified as :unsigned-long,
>>
>> but on windows x64, (ffi:size-of-foreign-type :unsigned-long) is 4, not
>> enough for a pointer,
> I think that the correct solution is to define uintptr_t that seems to
> be the correct type here. Moreover, it is part of C99, so we can rely on it.
> There is semi-related ticket for that here:
>
> https://gitlab.com/embeddable-common-lisp/ecl/-/work_items/768
>
>> so a value bigger than ffi:c-ulong-max failed internal test.
>>
>>
>> you can reproduce this issue on a window 64 platform(msys2)
>>
>>   >(ffi:make-pointer (+ 0 ffi:c-ulong-max) :void)
>>
>> #<foreign :VOID 0xffffffff>
>>
>>   > (ffi:make-pointer (+ 1 ffi:c-ulong-max) :void)
>>
>> Condition of type: TYPE-ERROR
>> 4294967296 is not of type (INTEGER 0 4294967295).
>> Available restarts:
>>
>> 1. (RESTART-TOPLEVEL) Go back to Top-Level REPL.
>> Broken at SI:BYTECODES. [Evaluation of: (FFI:MAKE-POINTER (+ 1
>> FFI:C-ULONG-MAX) :VOID)] In: #<process TOP-LEVEL 0x174235a0f30>.
>>
>>
>> more testing:
>>
>>   > (ffi:with-foreign-object (name '(:array :char 256))
>>      (ffi:make-pointer (ffi:pointer-address name) :pointer-void))
>>
>> Condition of type: TYPE-ERROR
>> 1598320958464 is not of type (INTEGER 0 4294967295).
>> Available restarts:
>>
>> 1. (RESTART-TOPLEVEL) Go back to Top-Level REPL.
>> Broken at SI:BYTECODES. [Evaluation of: (FFI:WITH-FOREIGN-OBJECT (NAME
>> (QUOTE (:ARRAY :CHAR 256))) (FFI:MAKE-POINTER (FFI:POINTER-ADDRESS NAME)
>> :POINTER-VOID))] In: #<process TOP-LEVEL 0x174235a0f30>.
>>   >>
>>
>>
>> with the following fix, just passed the test temporarily
>>
>> (defun make-pointer (addr type)
>>     (c-inline (type (size-of-foreign-type type) addr) (:object
>> :unsigned-long #+win64 :unsigned-long-long #-win64 :unsigned-long) :object
>>               "ecl_make_foreign_data(#0, #1, (void*)#2)"
>>               :side-effects t
>>               :one-liner t))
>>
>> for the pointer type, I think this is not a good solution.
>>
> I agree -your conclusion is correct. The proper solution will be to include uintptr_t type in base types, as :uintptr-t, and update make-pointer to use that. A similar issue is reported here:
>
> https://gitlab.com/embeddable-common-lisp/ecl/-/work_items/679
>
> Best regards,
> Daniel
>