Re: [xml] Memory leak / cleanup missing after node creation.

[Igor Zlatkovic <igor zlatkovic com>]

On 25.05.2004 16:31, Jose Commins wrote:
>     I see!  So in effect xmlBufferCreateSize does indeed allocate the 
> amount of memory I specify (my xml output buffers never go beyond 4K, so 
> I allocate 8192 just in case).

Don't worry about the size. As soon as the data is larger than the 
buffer, the buffer will grow but it will keep its new size. If the same 
data arrives in a future pass, it will fit into the buffer this time. A 
call to, for instance xmlBufferEmpty, will not restore the buffer's 
initial size.

>     In my app I keep the buffers persistent throughout threads, so I 
> don't constantly create/destroy buffers, just re-use them on the next 
> pass.  Seeing as I have to use xmlBufferEmpty or xmlBufferShrink after 
> each use, am I right in thinking that xmlBufferShrink is more optimal 
> since it doesn't clear the data (I am guessing here)?

No. xmlBufferShrink will remove data from the beginning of the buffer. 
It will not trim the unused memory from its end, as you might be led to 
believe. Unless you are working with large data chunks which cannot fit 
in your computer's memory, you don't need this function.

You should do what you did, call xmlBufferEmpty when you are done 
working with the data in the buffer. This will empty the buffer, but 
keep the allocated memory. Without calling xmlBufferEmpty, your each 
pass would be appending data to what the buffer contained in the 
previous pass. xmlNodeDump appends data to the buffer rather than 
replacing it, of course. How else would its recursive call on node's 
children work?

>     By the way, I have to reiterate Igor that you have been of 
> invaluable help and knowledge on these matters and I send my thanks again.

A thank expressed in cold beer pitchers is most welcome. :-)

Ciao,
Igor