Re: GC-proof resource classes

[ZombineDev via Digitalmars-d]

On Saturday, 29 August 2015 at 13:14:26 UTC, ponce wrote:

----------------

ensureNotInGC() is implemented like this:

----------------

void ensureNotInGC(string resourceName) nothrow
{
    debug
    {
        import core.exception;
        try
        {
            import core.memory;
            void* p = GC.malloc(1); // not ideal since it 
allocates
            return;
        }
        catch(InvalidMemoryOperationError e)
        {
            import core.stdc.stdio;
            fprintf(stderr, "Error: clean-up of %s incorrectly 
depends on destructors called by the GC.\n", resourceName.ptr);
            assert(false); // crash
        }
    }
}

--------------

...

BTW, you can use GC.free, instead of GC.malloc, with any non-zero 
invalid memory address, for example: 
http://dpaste.dzfl.pl/af0dc9aaa29d

A more robust solution would be to check if the gcx.running flag 
is raised, or if the GC lock is taken, like this: 
https://gist.github.com/ZombineDev/14076777dff7d879d659, however 
this is not currently possible, because the _gc variable in 
gc.proxy is private and by default gc.proxy is not part of the 
include files.

Since it's really straightforward to expose the information to 
the user, I think this would an easy enhancement.