Re: Surprising behaviour of std.experimental.allocator

[Elronnd via Digitalmars-d-learn]

On Thursday, 24 December 2020 at 16:12:31 UTC, Saurabh Das wrote:
This causes a segfault when run with rdmd -gx:
*snip*

First, here's a reduced version:

void main() {
        import std.experimental.allocator: allocatorObject, expandArray;
	import 
std.experimental.allocator.building_blocks.allocator_list: 
AllocatorList;
        import std.experimental.allocator.building_blocks.region: Region;
	import 
std.experimental.allocator.building_blocks.fallback_allocator: 
FallbackAllocator;
        import std.experimental.allocator.mallocator: Mallocator;
        import core.memory: GC;
        import std.stdio;

        enum MB = 1024 * 1024;

        {
                alias Alloc1 = FallbackAllocator!(
                                AllocatorList!(n => Region!Mallocator(MB)),
                                Mallocator);
                auto alloc1 = allocatorObject(Alloc1());

                GC.collect;
                alloc1.allocate(MB);
        }
        
	writeln(5); // this never gets printed; segfault happens upon 
exiting the above scope
}


I'm not 100% sure where the segfault comes from--though I think 
it's a problem with AllocatorList--but as a workaround, try 
replacing ‘AllocatorList!(n => Region!Mallocator(MB))’ with 
‘AllocatorList!(n => Region!Mallocator(MB), NullAllocator)’.