Ensure atomic_ops.c global symbols are always declared as extern 'C'

* src/atomic_ops.c (AO_pause): Declare as extern "C" if __cplusplus.
* src/atomic_ops.c [!_MSC_VER && !__MINGW32__ && !__BORLANDC__
|| AO_USE_NO_SIGNALS] (AO_fetch_compare_and_swap_emulation,
AO_compare_double_and_swap_double_emulation, AO_store_full_emulation):
Likewise.
* src/atomic_ops.c [(!_MSC_VER && !__MINGW32__ && !__BORLANDC__
|| AO_USE_NO_SIGNALS) && !AO_NO_PTHREADS] (AO_pt_lock): Likewise.
* src/atomic_ops_stack.c [AO_USE_ALMOST_LOCK_FREE] (AO_pause):
Likewise.
* src/atomic_ops.c (AO_pause): Move declaration up to have it
unconditionally.

2 files changed, 35 insertions, 2 deletions

diff --git a/src/atomic_ops.c b/src/atomic_ops.c
index 5f33a90..3c62fb5 100644
--- a/src/atomic_ops.c
+++ b/src/atomic_ops.c
@@ -53,6 +53,16 @@
 #undef AO_REQUIRE_CAS
 #include "atomic_ops.h" /* Without cas emulation! */
 
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+void AO_pause(int); /* defined below */
+
+#ifdef __cplusplus
+  } /* extern "C" */
+#endif
+
 #if !defined(_MSC_VER) && !defined(__MINGW32__) && !defined(__BORLANDC__) \
     || defined(AO_USE_NO_SIGNALS)
 
@@ -80,11 +90,28 @@
 # include "atomic_ops/sysdeps/standard_ao_double_t.h"
 #endif
 
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+AO_t AO_fetch_compare_and_swap_emulation(volatile AO_t *addr, AO_t old_val,
+                                         AO_t new_val);
+
+int AO_compare_double_and_swap_double_emulation(volatile AO_double_t *addr,
+                                                AO_t old_val1, AO_t old_val2,
+                                                AO_t new_val1, AO_t new_val2);
+
+void AO_store_full_emulation(volatile AO_t *addr, AO_t val);
+
 /* Lock for pthreads-based implementation.      */
 #ifndef AO_NO_PTHREADS
   pthread_mutex_t AO_pt_lock = PTHREAD_MUTEX_INITIALIZER;
 #endif
 
+#ifdef __cplusplus
+  } /* extern "C" */
+#endif
+
 /*
  * Out of line compare-and-swap emulation based on test and set.
  *
@@ -108,8 +135,6 @@ static AO_TS_t AO_locks[AO_HASH_SIZE] = {
   AO_TS_INITIALIZER, AO_TS_INITIALIZER, AO_TS_INITIALIZER, AO_TS_INITIALIZER,
 };
 
-void AO_pause(int); /* defined below */
-
 static void lock_ool(volatile AO_TS_t *l)
 {
   int i = 0;
diff --git a/src/atomic_ops_stack.c b/src/atomic_ops_stack.c
index 5d7995f..bb9c3ad 100644
--- a/src/atomic_ops_stack.c
+++ b/src/atomic_ops_stack.c
@@ -36,8 +36,16 @@
 
 #ifdef AO_USE_ALMOST_LOCK_FREE
 
+# ifdef __cplusplus
+    extern "C" {
+# endif
+
   void AO_pause(int); /* defined in atomic_ops.c */
 
+# ifdef __cplusplus
+    } /* extern "C" */
+# endif
+
 /* LIFO linked lists based on compare-and-swap.  We need to avoid       */
 /* the case of a node deletion and reinsertion while I'm deleting       */
 /* it, since that may cause my CAS to succeed eventhough the next       */