[Vortex] Change notification: vortex-voidptr-update-01

[Francis Brosnan Blazquez]

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    Change Id: vortex-voidptr-update-01
 Project name: Vortex Library
  Included in: already included, to be shipped with next stable release
               1.0.8
       Status: NOTIFY
       Author: Francis Brosnan Blázquez

Motivation
~~~~~~~~~~

The change introduced accommodates the Vortex API dealing with sending
data operations. Currently the type used is "const char *", and the
change introduced replace it with a "const void *" declaration to
enforce the fact that the API sends groups of octets without looking
into the application data.

Change Description
~~~~~~~~~~~~~~~~~~

The API update introduces a broad type (void *) which is compatible
with (unsigned char *) and (char *), and do not require casting. It is
expected no change to code developed with previous revisions.

In addition, all function that receive these kind of pointers to refer
to arbitrary binary content are also updated to use the type "size_t"
rather than a plain "int". Again, no change it is supposed to be
required.

The following API function have been updated:

  - vortex_channel_send_msg 
  - vortex_channel_send_msg_and_wait
  - vortex_channel_send_rpy
  - vortex_channel_send_ans_rpy
  - vortex_channel_send_err
  - vortex_frame_get_payload

Solution to incompatibility
~~~~~~~~~~~~~~~~~~~~~~~~~~~

There is only one function that will produce compilation warnings due
to the change introduced: vortex_frame_get_payload.

This function was returning the payload content as "char*" but now it
is returned as "const void *". This will allow to properly conform
with the fact that the content could be (char *) or (unsigned char *). 

However, the caller will have to include a cast to properly configure
the kind of content, i.e:

   reference = (char*) vortex_frame_get_payload (frame);

References
~~~~~~~~~~
[1] Project link: 
    http://vortex.aspl.es

[2] Change notification published by the project:
    http://vortex.aspl.es/doc.html

[3] Change notification definition
    http://www.aspl.es/change/change-notification.txt

-- 
Francis Brosnan Blazquez <francis at aspl.es>
Advanced Software Production Line, S.L.