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I've read article in LinuxJournal about Boehm-Demers-Weiser garbage collector library. I'm interesting to use it in my library instead of my own reference counting implementation.
I have only one question: is it possible to use gc only for my shared library and still use malloc/free in the main application? I'm not quite understand how gc checks the heap so I'm worrying about performance of gc in that case and possible side effects.
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The Boehm GC is a conservative collector, which means it assumes everything (on pointer boundaries) is a pointer. This means that it can find false positive references, like an integer which coincidentally has the value of an address in the heap.
A garbage collector's duties are to pick up trash and recycling and transport it to a landfill, sorting facility, or recycling center.
In the common language runtime (CLR), the garbage collector (GC) serves as an automatic memory manager. The garbage collector manages the allocation and release of memory for an application. Therefore, developers working with managed code don't have to write code to perform memory management tasks.
A C++ program can contain both manual memory management and garbage collection happening in the same program. According to the need, either the normal pointer or the specific garbage collector pointer can be used. Thus, to sum up, garbage collection is a method opposite to manual memory management.
The example in the manual states:
It is usually best not to mix garbage-collected allocation with the system
malloc-free. If you do, you need to be careful not to store pointers to the garbage-collected heap in memory allocated with the systemmalloc.
And more specifically for C++:
In the case of C++, you need to be especially careful not to store pointers to the garbage-collected heap in areas that are not traced by the collector. The collector includes some alternate interfaces to make that easier.
Looking at the source code in the manual you will see the garbage-collected memory is handled through specific calls, hence, the management is handled separately (either by the collector or manually). So as long your library handles its internals properly and doesn't expose collected memory, you should be fine. You don't know how other libraries manage their memory and you can use them as well, don't you? :)
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