Re: How to get binary data to callback function

is this what you mean?

these are pre-allocating space for a return value to be filled by the C
function:

    sense_buffer = create_string_buffer(64)
    self.mx_sb_len = len(sense_buffer)
    #io_hdr.sbp=addressof(sense_buffer)
    io_hdr.sbp=cast(sense_buffer,c_char_p)
    io_hdr.sb_len_wr = 0 # initialize just in case...

    page_buffer=create_string_buffer(sz)
    io_hdr.dxfer_len = sz
    #io_hdr.dxferp = addressof(page_buffer)
    io_hdr.dxferp = cast(page_buffer,c_char_p)

    if self.debug & Drobo.DBG_HWDialog:
      print "4 before ioctl, sense_buffer_len=", io_hdr.mx_sb_len

    i=ioctl(self.sg_fd, sg_io_hdr.SG_IO, io_hdr)


On Tue, Dec 22, 2009 at 6:13 PM, Nikolaus Rath <[email protected]> wrote:

> Hello,
>
> When I define a callback function with a prototype of
>
>   ctypes.CFUNCTYPE(None, ctypes.c_char_p, ctypes.c_int)
>
> The function receives a true Python string. However, my data isn't
> actually \0 terminated, and I would like to call string_at(par1, par2)
> to get the binary data. But how do I get ctypes to pass the c_char_p
> object to my function, rather than the unwrapped string?
>
> Thanks,
>
>   -Nikolaus
>
> --
>  »Time flies like an arrow, fruit flies like a Banana.«
>
>  PGP fingerprint: 5B93 61F8 4EA2 E279 ABF6  02CF A9AD B7F8 AE4E 425C
>
>
>
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