I'll make the modifications for #1 and #2.

The text at the top (#3) was put there by someone else. I just added to the page. It didn't look right to me, but it's been there for a while so I didn't touch it. :)

cr

On May 11, 2010, at 5:33 PM, Wayne Meissner wrote:

> It looks pretty good.
> 
> A couple of nits:
> 
> 1) The LibC module can just use:
>   ffi_lib FFI::Library::LIBC
> 
> ffi knows that means "whatever the libc on this system is supposed to
> be", since its a pretty common library people want to map in, and the
> name differs across platforms (e.g. on linux, its libc.so.6, macos is
> libc.dylib, windows is msvcrt.dll, aix is something weird, etc.
> 
> 2) The first arg to MemoryPointer.new can in fact be either a symbol,
> or anything that responds to #size.
> e.g.
>  class S < FFI::Struct
>    layout :i, :int
>  end
>  FFI::MemoryPointer.new(S, 1, false)  # Will allocate space for one
> instance of S, without clearing the memory first
> 
> 3) The bit at the top about copying pointers is ... confusing.  A
> pointer is merely a Fixnum that holds a native memory address, so
> there is no need to do anything special to "copy" a pointer - just
> assign it to a like you would any other Fixnum.  Think of "Pointer" as
> "fixnum with methods to read/write the native memory at the address".
> 
> The example:
> 
> b = MemoryPointer.new(:pointer).write_pointer(some_pointer.read_pointer)
> 
> Doesn't do what you think.  It reads a pointer from the memory
> pointed-to by some_pointer, allocates a new chunk of memory, and
> writes that pointer value into that memory - it doesn't copy the value
> of some_pointer to a new pointer.
> 
> 
> 
> 
> 
> 
> 
> 
> On 12 May 2010 02:02, Chuck Remes <cremes.devlist@mac.com> wrote:

>> I just wrote an update to the wiki page on pointers at http://wiki.github.com/ffi/ffi/pointers
>> 
>> I'd appreciate it if someone more knowledgeable would check it over (the bottom section under the sub-heading) and verify that what I wrote is correct. It seems to be working for me but I've been wrong before! :)
>> 
>> cr
>> 
>>