When I specified a -od, <objpath> , a double level of 2 directories was created in my current directory, and the object file place theirin, namely <./objpath/objpath/myobjfile.o, for both linux, dmd, dmd 1.0 and dmd 2.0.

An examination of the mars.c source and module.c source for the string "global.params.objdir" shows under these conditions the string passed in the options is concantenated twice.

In mars.c

line 713 if (global.params.link)
	{..

	if(global.params.objname)
	{
	// name as the exe file.

		if (global.params.objdir)
		{
		..
		global.params.objname = 

FileName::combine(global.params.objdir,name)


And in module.c

line 136

if (global.params.objname)
	// objdir must be already combined by here!
	argobj = global.params.objname;

..

if (!FileName::absolute(argobj))
{
// objdir is combined again, because already in global.params.objname

	argobj = 

FileName::combine(global.params.objdir, argobj);
}

I was testing a little XML configuration build tool, and dmd refused to make just one level of relative directory.

The workaround would seem to be to work out the absolute path and pass that to the option.