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<div class="moz-cite-prefix">Op 21-08-13 13:04, Wiley, Glen schreef:<br>
</div>
<blockquote cite="mid:CE3A16E4.1283E%25gwiley@verisign.com"
type="cite">
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<div>As we are working on our implementation of the getdns API I
realized that there doesn't seem to be a way for the helper
functions that handle the dict and list types to get to the user
defined allocator. The allocator is specified in a context,
however the signatures of the helper functions do not accept a
context as an argument. There are a few ways to address this:</div>
<div><br>
</div>
<ol>
<li>Add a context as an argument to the helper functions. This
is probably the least disruptive to the rest of the API.</li>
<li>Change the way a user defined allocator is defined. It is
likely that the application developer would expect to use the
same allocator throughout the application so it may be enough
to make an assignment outside a context as an initialization
step.</li>
</ol>
<div>I am sure that there are other options, but I think approach
#2 would be a comfortable way to handle this.</div>
</blockquote>
I agree.<br>
<br>
Also the custom memory management functions that may be specified
have the same prototype as the standard C functions. This restricts
the type of custom memory functions to ones that either do no custom
memory bookkeeping, or have the needed bookkeeping-journal in
globals. Having global custom memory functions in a individual
getdns context feels as a discrepancy. A global registration
function would suit better. For example, just like the one in
libevent:<br>
<br>
<pre><tt><strong>void</strong> getdns_set_mem_functions(<strong>void</strong> *(*malloc_fn)(size_t sz),
<strong>void</strong> *(*realloc_fn)(<strong>void</strong> *ptr, size_t sz),
<strong>void</strong> (*free_fn)(<strong>void</strong> *ptr));</tt></pre>
<br>
I prefer custom memory management functions to be implementation
specific in the API, just like setting the event base is. I feel
there are too many variables to consider to have a conclusive
solution that fits all. It would also allow for implementations to
match this capability with the capabilities of the event base.<br>
<br>
<br>
-- Willem<br>
<br>
<br>
PS. An implementations that would allow bookkeeping memory
functions, could have a registration function that would look
something like this:<br>
<pre><tt><strong>void</strong> getdns_context_set_mem_functions(getdns_context_t<strong> </strong>context<strong>,
void</strong> *(*malloc_fn)(<b>void</b> *journal, size_t sz),
<strong> void</strong> *(*realloc_fn)(<b>void</b> *journal, <strong>void</strong> *ptr, size_t sz),
<strong> void</strong> (*free_fn)(<strong>void</strong> *journal, <strong>void</strong> *ptr));</tt></pre>
<br>
Of course it would then also need custom list and dict create
functions:<br>
<br>
<pre><tt>struct getdns_list * getdns_list_create_custom(getdns_context_t<strong> </strong>context<strong>);</strong></tt></pre>
<pre><tt>struct getdns_dict * getdns_dict_create_custom(getdns_context_t<strong> </strong>context<strong>);
</strong></tt></pre>
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