Re: [boost] [boost.atomic] linker error with gcc 4.1.2

Subject: Re: [boost] [boost.atomic] linker error with gcc 4.1.2
From: Oliver Kowalke (k-oli_at_[hidden])
Date: 2010-03-03 12:57:15

Jamie Allsop schrieb:
> With gcc 4.1.2 (gcc 4.3.x is fine) I am seeing this linker error:
> 
> .build/debug/working/SourceOne.o:
> In function `void 
> boost::detail::atomic::platform_atomic_thread_fence<boost::memory_order>(boost::memory_order)': 
> 
> /thirdparty/boost/boost_1_42/boost/smart_ptr/detail/shared_count.hpp:229: 
> multiple definition of `void 
> boost::detail::atomic::platform_atomic_thread_fence<boost::memory_order>(boost::memory_order)' 
> 
> .build/debug/working/SourceTwo.o:
> /thirdparty/boost/boost_1_42/boost/atomic/detail/gcc-x86.hpp:63: first 
> defined here
> 
> Which doesn't make a lot of sense at first glance, but on closer 
> inspection I see that:
> 
> boost/atomic/detail/base.hpp defines platform_atomic_thread_fence as:
> 
> template<typename T>
> static inline void platform_atomic_thread_fence(T order)
> {
>     /* FIXME: this does not provide
>     sequential consistency, need one global
>     variable for that... */
>     platform_atomic<int> a;
>     a.exchange(0, order);
> }
> 
> and then it is defined as a specialisation in:
> 
> boost/atomic/detail/gcc-x86.hpp as:
> 
> template<>
> void platform_atomic_thread_fence(memory_order order)
> {
>     switch(order) {
>         case memory_order_seq_cst:
>             full_fence();
>         case memory_order_acquire:
>         case memory_order_consume:
>         case memory_order_acq_rel:
>         case memory_order_release:
>             __asm__ __volatile__ ("" ::: "memory");
>         default:;
>     }
> }
> 
> Is this a compiler error or should the specialisation be declared as:
> 
> template<>
> inline void platform_atomic_thread_fence(memory_order order)
> 
> (which will work)
> 
> Suggestions?
> Jamie

use

static inline void platform_atomic_thread_fence(memory_order order)
{ ... }