Re: Wrong guile-bytestructures description for gnunet progress-info struct with unions

[Taylan Ulrich Bayırlı/Kammer]

Amirouche Boubekki <address@hidden> writes:

> I triple checked the %fs-progress-info definition, it's correct,
> but I still get incorrect value for status field, see download.scm
> line 13.

Wow, GNUNET_FS_ProgressInfo is hell of a struct. :-)

I also checked the bytestructure definition just in case but yes it
seems correct.

Here are some possibilities I can think of, wildly speculatively.

- %time-relative is defined wrong (I couldn't find the corresponding
  GNUNET_TIME_Relative definition to compare)

- %crypto-ecdsa-public-key is defined wrong (I couldn't find the
  corresponding GNUNET_CRYPTO_EcdsaPublicKey definition to compare)

If both of those are correct, further possibilities would be:

- Some or all of the structs in the C code are "packed".

- There's a bug in bytestructures.

To rule out these two, you can use a simple test case: write a tiny C
lib with a function that allocates a GNUNET_FS_ProgressInfo struct,
writes to its status field, and returns a pointer to it.  Load the lib
from Scheme, call the function through FFI... you know the rest; see if
you get the correct value when you read the status field from Scheme.

If you get the correct result, further possibilities:

- The wrong pointer is being passed to pointer->bytestructure for
  whatever reason.

- The status field is being read at the wrong time for whatever reason.
  (Be extra careful if the code is multi-threaded.)

- The struct is being deallocated before Scheme code is done with it.


Hope that helps,
Taylan