On Thursday, 17 July 2014 at 16:28:00 UTC, Tero wrote:
Just watched Don's DConf 2014 talk where he said D has to be ruthless about memory inefficiency. Here's one thing that I think could help avoid unnecessary garbage: built-in syntax for this:

import core.stdc.stdlib : alloca;
ubyte[] buffer = (cast(ubyte*) alloca(bufsize)) [0 .. bufsize];

Often bufsize is not known at compile-time but it won't change after the buffer allocation. So there's no reason to create garbage other than the *inconvenience* of using alloca. Allocating in the stack seems ideal so I'd encourage that by a
clean syntax. I keep missing this feature.

In theory there would probably be an allocator that uses alloca
when Andrei's std.allocator makes it in. Using alloca is actually
rather problematic in D right now though (with DMD at least)...
https://issues.dlang.org/show_bug.cgi?id=12820

Also, there used to be a built in syntax, 'scope foo = new Foo()' that would allocate on the stack, but that's deprecated now (and seemed to segfault when I tried it).

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