Table of Contents
The file <ext/concurrence.h>
contains all the higher-level
constructs for playing with threads. In contrast to the atomics layer,
the concurrence layer consists largely of types. All types are defined within namespace __gnu_cxx.
@@ -17,7 +16,7 @@ that support multiple threads.)
available locking
policies: _S_single, _S_mutex,
and _S_atomic.
-
_S_single
Indicates single-threaded code that does not need locking. +
_S_single
Indicates single-threaded code that does not need locking.
_S_mutex
Indicates multi-threaded code using thread-layer abstractions.
_S_atomic
Indicates multi-threaded code using atomic operations.
The compile-time constant __default_lock_policy is set
@@ -33,7 +32,7 @@ critical sections, while retaining exception-safety.
These types have been superseded in the ISO C++ 2011 standard by the
mutex and lock types defined in the header
<mutex>.
-
Two functions and one type form the base of atomic support.
The type _Atomic_word is a signed integral type
supporting atomic operations.
@@ -47,7 +46,7 @@ void
__atomic_add_dispatch(volatile _Atomic_word*, int);
Both of these functions are declared in the header file
<ext/atomicity.h>, and are in namespace __gnu_cxx.
-
+
__exchange_and_add_dispatch
@@ -66,7 +65,7 @@ __exchange_and_add_dispatch
Calls through to either of: -
__exchange_and_add
+
__exchange_and_add
Multi-thread version. Inlined if compiler-generated builtin atomics can be used, otherwise resolved at link time to a non-builtin code sequence. @@ -91,4 +90,4 @@ _GLIBCXX_WRITE_MEM_BARRIER
Which expand to the appropriate write and read barrier required by the host hardware and operating system. -