When I was looking at dmd's options, I found this:
m64 generate 64 bit code

I guessed it behaves like gcc (m64 for 64 bit code and m32 for 32 bit code, assuming you have the multilibs), so I did a rebuild.
This is the structure of my /opt/dmd-dev

   |-bin (64-bit version of dmd, impcnvgen, idgen, optabgen, plus dmd.conf)
   |-import
   |---core
   |-----stdc
   |-----sync
   |-----sys
   |-------osx
   |---------mach
   |-------posix
   |---------arpa
   |---------net
   |---------netinet
   |---------sys
   |-------windows
   |-lib32 (libdruntime-linux32.a and libphobos.a)
   |-lib64 (libdruntime-linux64.a and libphobos.a)
   |-phobos
   |---std
   |-----c
   |-------freebsd
   |-------linux
   |-------osx
   |-------windows
   |-----internal
   |-------math
   |-------windows
   |-----net
   |-----windows

And this is my dmd.conf:
[Environment]
DFLAGS=-I/opt/dmd-dev/import -I/opt/dmd-dev/phobos -L-L/opt/dmd-dev/lib32 -L-L/opt/dmd-dev/lib64

dmd -32 works fine. But either dmd or dmd -m64 doesn't work, e.g:
$ dmd -m64 einstein2b.d
/usr/bin/ld: skipping incompatible /opt/dmd-dev/lib32//libphobos2.a when searching for -lphobos2
/usr/bin/ld: cannot find -lphobos2
collect2: ld returned 1 exit status
--- errorlevel 1

I wonder why ld searches at /opt/dmd-dev/lib32, whereas it should be /opt/dmd-dev/lib64 ?

>   |-bin (64-bit version of dmd, impcnvgen, idgen, optabgen, plus dmd.conf)

^^ You don't need impcnvgen, idgen and optabgen.

Uhmm OK. But what does it do with dmd? I mean, dmd -m64 still doesn't work.

Anyway, I used to build both versions and put this on my ~/.bashrc:
alias dmd32='/opt/dmd-dev/bin32/dmd'
alias dmd64='/opt/dmd-dev/bin64/dmd'

But if a single dmd can generate both 32 and 64 bit code, it will be very convenient.

On 02/12/2012 06:58 PM, Trass3r wrote:
>>   |-bin (64-bit version of dmd, impcnvgen, idgen, optabgen, plus dmd.conf)
> 
> ^^ You don't need impcnvgen, idgen and optabgen.

On 02/12/2012 09:26 AM, Andre Tampubolon wrote:
> And this is my dmd.conf:
> [Environment]
> DFLAGS=-I/opt/dmd-dev/import -I/opt/dmd-dev/phobos -L-L/opt/dmd-dev/lib32 -L-L/opt/dmd-dev/lib64

Try adding -L--no-warn-search-mismatch

-- 
Mike Wey

Hmm doesn't work. The same error still applies.

On 02/12/2012 08:36 PM, Mike Wey wrote:
> On 02/12/2012 09:26 AM, Andre Tampubolon wrote:
>> And this is my dmd.conf:
>> [Environment]
>> DFLAGS=-I/opt/dmd-dev/import -I/opt/dmd-dev/phobos -L-L/opt/dmd-dev/lib32 -L-L/opt/dmd-dev/lib64
> 
> Try adding -L--no-warn-search-mismatch
> 

On Sunday, 12 February 2012 at 08:26:07 UTC, Andre Tampubolon wrote:

>  |-lib32 (libdruntime-linux32.a and libphobos.a)
>  |-lib64 (libdruntime-linux64.a and libphobos.a)

... Are you sure it's libphobos.a and not libphobos2.a?

> dmd -32 works fine. But either dmd or dmd -m64 doesn't work, e.g:
> $ dmd -m64 einstein2b.d
> /usr/bin/ld: skipping incompatible /opt/dmd-dev/lib32//libphobos2.a when searching for -lphobos2
> /usr/bin/ld: cannot find -lphobos2
> collect2: ld returned 1 exit status
> --- errorlevel 1
>
> I wonder why ld searches at /opt/dmd-dev/lib32, whereas it should be /opt/dmd-dev/lib64 ?

Actually it searches both directories all the time because dmd.conf adds the two to the link path. The theory is that the linker should just discard the wrong one.

--
Michel Fortin
michel.fortin@michelf.com
http://michelf.com

On 02/12/2012 03:21 PM, Andre Tampubolon wrote:
> Hmm doesn't work. The same error still applies.
>
> On 02/12/2012 08:36 PM, Mike Wey wrote:
>> On 02/12/2012 09:26 AM, Andre Tampubolon wrote:
>>> And this is my dmd.conf:
>>> [Environment]
>>> DFLAGS=-I/opt/dmd-dev/import -I/opt/dmd-dev/phobos -L-L/opt/dmd-dev/lib32 -L-L/opt/dmd-dev/lib64
>>
>> Try adding -L--no-warn-search-mismatch
>>
>

Can you post the output of dmd when compiling with: "-v" ?

-- 
Mike Wey

This is the log:
http://pastebin.com/bGt7MVd2

Anyway, I found the culprit, which is ~/dmd.conf. The content is:
[Environment]
DFLAGS=-I/opt/dmd-dev/import -I/opt/dmd-dev/phobos -L-L/opt/dmd-dev/lib32/

That's why dmd couldn't locate the 64 bit libs. I should use only 1 dmd.conf, which is located in /opt/dmd-dev/bin. Now -m64 works fine :)

On 02/12/2012 09:45 PM, Mike Wey wrote:
> On 02/12/2012 03:21 PM, Andre Tampubolon wrote:
>> Hmm doesn't work. The same error still applies.
>>
>> On 02/12/2012 08:36 PM, Mike Wey wrote:
>>> On 02/12/2012 09:26 AM, Andre Tampubolon wrote:
>>>> And this is my dmd.conf:
>>>> [Environment]
>>>> DFLAGS=-I/opt/dmd-dev/import -I/opt/dmd-dev/phobos -L-L/opt/dmd-dev/lib32 -L-L/opt/dmd-dev/lib64
>>>
>>> Try adding -L--no-warn-search-mismatch
>>>
>>
> 
> Can you post the output of dmd when compiling with: "-v" ?
> 

Sorry, libphobos.a is a typo :)

On 02/12/2012 09:42 PM, Michel Fortin wrote:
> On Sunday, 12 February 2012 at 08:26:07 UTC, Andre Tampubolon wrote:
> 
>>  |-lib32 (libdruntime-linux32.a and libphobos.a)
>>  |-lib64 (libdruntime-linux64.a and libphobos.a)
> 
> ... Are you sure it's libphobos.a and not libphobos2.a?
> 
>> dmd -32 works fine. But either dmd or dmd -m64 doesn't work, e.g:
>> $ dmd -m64 einstein2b.d
>> /usr/bin/ld: skipping incompatible /opt/dmd-dev/lib32//libphobos2.a when searching for -lphobos2
>> /usr/bin/ld: cannot find -lphobos2
>> collect2: ld returned 1 exit status
>> --- errorlevel 1
>>
>> I wonder why ld searches at /opt/dmd-dev/lib32, whereas it should be /opt/dmd-dev/lib64 ?
> 
> Actually it searches both directories all the time because dmd.conf adds the two to the link path. The theory is that the linker should just discard the wrong one.
> 
> -- 
> Michel Fortin
> michel.fortin@michelf.com
> http://michelf.com
>