Issue 1479: Fence functions should be extern "C"

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1479. Fence functions should be `extern "C"`

Section: 33.5.11 [atomics.fences] Status: C++11 Submitter: INCITS Opened: 2010-08-25 Last modified: 2016-01-28

Priority: Not Prioritized

View all other issues in [atomics.fences].

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Discussion:

Addresses US-179

The fence functions (33.5.11 [atomics.fences] p.5 + p.6) should be extern "C", for C compatibility.

[2011-02-16 Reflector discussion]

Moved to Tentatively Ready after 6 votes.

Proposed resolution:

Change 33.5.2 [atomics.syn], header <atomic> synopsis as indicated:

namespace std {
  [..]
  // 29.8, fences
  extern "C" void atomic_thread_fence(memory_order);
  extern "C" void atomic_signal_fence(memory_order);  
}

Change 33.5.11 [atomics.fences], p. 5 and p. 6 as indicated:
```
extern "C" void atomic_thread_fence(memory_order);
```
5 Effects: depending on the value of order, this operation: [..]
```
extern "C" void atomic_signal_fence(memory_order);  
```
6 Effects: equivalent to atomic_thread_fence(order), except that synchronizes with relationships are established only between a thread and a signal handler executed in the same thread.

1479. Fence functions should be extern "C"

1479. Fence functions should be `extern "C"`