[Rd] R/C++/memory leaks

Ernest Turro ernest.turro at ic.ac.uk
Mon Feb 26 14:20:42 CET 2007

On 26 Feb 2007, at 10:51, Hin-Tak Leung wrote:
> Ernest Turro wrote:
>> Dear all,
>> I have wrapped a C++ function in an R package. I allocate/ 
>> deallocate  memory using C++ 'new' and 'delete'. In order to allow  
>> user  interrupts without memory leaks I've moved all the delete  
>> statements  required after an interrupt to a separate C++ function  
>> freeMemory(),  which is called using on.exit() just before the .C 
>> () call.
>> I am concerned about the following. In square brackets you see  
>> R's  total virtual memory use (VIRT in `top`):
>> 1) Load library and data [178MB] (if I run gc(), then [122MB])
>> 2) Just before .C [223MB]
>> 3) Just before freeing memory [325MB]
>> 4) Just after freeing memory [288MB]
>> 5) After running gc() [230MB]
>> So although the freeMemory function works (frees 37MB), R ends up   
>> using 100MB more after the function call than before it. ls()  
>> only  returns the data object so no new objects have been added to  
>> the  workspace.
>> Do any of you have any idea what could be eating this memory?
>> Many thanks,
>> Ernest
>> PS: it is not practical to use R_alloc et al because C++  
>> allocation/ deallocation involves constructors/destructors and  
>> because the C++  code is also compiled into a standalone binary (I  
>> would rather avoid  maintaining two separate versions).
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel

> Read the help page of gc(). You need to run it with reset=TRUE for
> the usage to drop back to original. i.e. gc(reset=TRUE). gc() on its
> own doesn't quite do what you think it would do.

Thanks, but in this case it barely makes a difference.. :(

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