llvm dev - Dec 2009 - [LLVMdev] clang error: multiple definition of `gnu_dev_*'

When trying to link more than one object files compiled with clang, I run into
errors of the following type:

$ clang -fblocks -g -I$HOME/opt/include -L$HOME/opt/lib/ -o helloworld
helloworld.c hello.o world.o -lBlocksRuntime
world.o: In function `gnu_dev_major':
/usr/include/sys/sysmacros.h:43: multiple definition of `gnu_dev_major'
hello.o:/usr/include/sys/sysmacros.h:43: first defined here
world.o: In function `gnu_dev_minor':
/usr/include/sys/sysmacros.h:49: multiple definition of `gnu_dev_minor'
hello.o:/usr/include/sys/sysmacros.h:49: first defined here
world.o: In function `gnu_dev_makedev':
/usr/include/sys/sysmacros.h:55: multiple definition of `gnu_dev_makedev'
hello.o:/usr/include/sys/sysmacros.h:55: first defined here
collect2: ld returned 1 exit status
clang: error: linker command failed with exit code 1 (use -v to see invocation)

The platform I'm building this on is x86_64 GNU/Linux.
FWIW, here is how the source files look:

$ cat hello.c
#include <stdio.h>
#include <stdlib.h>
#include <Block.h>
void hello(void)
{
        void (^a)(void) = ^{
                printf("Hello");
        };
        a();
}

$ cat world.c
#include <stdio.h>
#include <stdlib.h>
#include <Block.h>
void world(void)
{
        void (^a)(void) = ^{
                printf("world");
        };
        a();
}

The error disappears if I take off one or both instances of the
"#include <stdlib.h>"
line.

Is this a clang issue?

Thanks,
Abhishek

On 14/12/09 13:57, Abhishek Kulkarni wrote:
> When trying to link more than one object files compiled with clang, I run
into
> errors of the following type:
>
> $ clang -fblocks -g -I$HOME/opt/include -L$HOME/opt/lib/ -o helloworld
> helloworld.c hello.o world.o -lBlocksRuntime
> world.o: In function `gnu_dev_major':
> /usr/include/sys/sysmacros.h:43: multiple definition of `gnu_dev_major'
> hello.o:/usr/include/sys/sysmacros.h:43: first defined here
> world.o: In function `gnu_dev_minor':
> /usr/include/sys/sysmacros.h:49: multiple definition of `gnu_dev_minor'
> hello.o:/usr/include/sys/sysmacros.h:49: first defined here
> world.o: In function `gnu_dev_makedev':
> /usr/include/sys/sysmacros.h:55: multiple definition of
`gnu_dev_makedev'
> hello.o:/usr/include/sys/sysmacros.h:55: first defined here
> collect2: ld returned 1 exit status
> clang: error: linker command failed with exit code 1 (use -v to see
invocation)
>
I've recently been playing around with using Clang as the system 
compiler on a Gentoo system and found several packages that did 
something similar. The fix appears to be to add the -std=c89 option; 
from memory Clang defaults to c99 (while GCC defaults to c89) and there 
is a difference in the handling of inlining functions. One instance of 
this was also fixed by compiling Clang/LLVM from SVN, so if the c89 
option doesn't fix it maybe give that a go (if you aren't already).

Hope that helps,

Andrew

On Sun, Dec 13, 2009 at 10:42 PM, Andrew Jeffery <andrew at aj.id.au>
wrote:
> On 14/12/09 13:57, Abhishek Kulkarni wrote:
>> When trying to link more than one object files compiled with clang, I
run into
>> errors of the following type:
>>
>> $ clang -fblocks -g -I$HOME/opt/include -L$HOME/opt/lib/ -o helloworld
>> helloworld.c hello.o world.o -lBlocksRuntime
>> world.o: In function `gnu_dev_major':
>> /usr/include/sys/sysmacros.h:43: multiple definition of
`gnu_dev_major'
>> hello.o:/usr/include/sys/sysmacros.h:43: first defined here
>> world.o: In function `gnu_dev_minor':
>> /usr/include/sys/sysmacros.h:49: multiple definition of
`gnu_dev_minor'
>> hello.o:/usr/include/sys/sysmacros.h:49: first defined here
>> world.o: In function `gnu_dev_makedev':
>> /usr/include/sys/sysmacros.h:55: multiple definition of
`gnu_dev_makedev'
>> hello.o:/usr/include/sys/sysmacros.h:55: first defined here
>> collect2: ld returned 1 exit status
>> clang: error: linker command failed with exit code 1 (use -v to see
invocation)
>>
>
> I've recently been playing around with using Clang as the system
> compiler on a Gentoo system and found several packages that did
> something similar. The fix appears to be to add the -std=c89 option;
Thanks, that worked!
> from memory Clang defaults to c99 (while GCC defaults to c89) and there
> is a difference in the handling of inlining functions. One instance of
> this was also fixed by compiling Clang/LLVM from SVN, so if the c89
> option doesn't fix it maybe give that a go (if you aren't already).
Yes, I was compiling from the current trunk r91244.
>
> Hope that helps,
>
> Andrew
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