On Wed, 14 Apr 2010 17:19:53 -0400, Joseph Wakeling
<joseph.wakel...@webdrake.net> wrote:
/////////////////////////////////////////////////////////////////////////
version(Tango) {
import tango.stdc.stdio: printf;
} else {
import std.stdio: printf;
}
void main()
{
double[] x;
for(uint i=0;i<100;++i) {
x.length = 0;
for(uint j=0;j<5_000;++j) {
for(uint k=0;k<1_000;++k) {
x ~= j*k;
}
}
printf("At iteration %u, x has %u elements.\n",i,x.length);
}
}
/////////////////////////////////////////////////////////////////////////
I noticed that when compiled with LDC the memory usage stays constant,
but in DMD the memory use blows up. Is this a D1/D2 difference (with D2
having the more advanced features that require preservation of memory)
or is it a bug in one or the other of the compilers ... ?
It is because D2 is more advanced in preserving memory. In D1, setting
length to zero is equivalent to also assuming it can append safely.
One thing I forgot about, there is currently a design flaw in D2 array
appending which will keep around a certain number of arrays even after all
references have been removed (i.e. the arrays should be collectable, but
they are not collected by the GC). I have a clear path on how to fix
that, but I haven't done it yet.
See this bugzilla report:
http://d.puremagic.com/issues/show_bug.cgi?id=3929
This might also help explain why the memory blows up.
-Steve
