Appendix B. Brief comparison of concurrency libraries
Concurrency and multithreading support in programming languages and libraries aren’t something new, even though standardized support in C++ is new. For example, Java has had multithreading support since it was first released, platforms that conform to the POSIX standard provide a C interface for multithreading, and Erlang provides support for message-passing concurrency. There are even C++ class libraries such as Boost that wrap the underlying programming interface for multithreading used on any given platform (whether it’s the POSIX C interface or something else) to provide a portable interface across the supported platforms.
For those who are already experienced in writing multithreaded applications and would like to use that experience to write code using the new C++ multithreading facilities, this appendix provides a comparison between the facilities available in Java, POSIX C, C++ with the Boost Thread Library, and C++11, along with cross-references to the relevant chapters of this book.
|
Feature |
Java |
POSIX C |
Boost threads |
C++11 |
Chapter reference |
|---|---|---|---|---|---|
| Starting threads | java.lang.thread class | pthread_t type and associated API functions: pthread_create(), pthread_detach(), and pthread_joint () | boost : : thread class and member functions | std : : thread class and member functions | Chapter 2 |
| Mutual exclusion | synchronized blocks | pthread_mutex_t type and associated API functions: pthread_mutex_lockt), pthread_mutex unlock(), etc. | boost : :mutex class andmember functions, boost::lock_guard<> and boost :: unique_lock<> templates | std: :mutex class and member functions, std:: lock_guardo and std: :unique_lock<> templates | Chapter 3 |
| Monitors/ waits for a predicate | wait() and notify () methods of the java.lang. Object class, used inside synchronized blocks | pthread_cond_t type and associated API functions: pthread_cond_wait(), pthread_cond_timed_wait ( ), etc. | boost:: condition_variable and boost:: condition_variable_any classes and member functions | std:: condition variable and std:: condition_variable any classes and member functions | Chapter 4 |
| Atomic operations and concurrency-aware memory model | volatile variables, the types in the java.util.concurrent.atomic package | N/A | N/A | std::atomic_xxx types, std: :atomic<> class template, std::atomic_thread_fence ( ) function | Chapter 5 |
| Thread-safe containers | The containers in the java.util.concurrentpackage | N/A | N/A | N/A | Chapters 6 and 7 |
| Futures | java.util.concurrent.future interface and associated classes | N/A | boost :: unique_future<> and boost :: shared_future<> class templates | std: : future<>, std::shared_future<> and std::atomic_future<> class templates | Chapter 4 |
| Thread pools | java.util.concurrent.ThreadPoolExecutor class | N/A | N/A | N/A | Chapter 9 |
| Thread interruption | interrupt ( ) method of java.lang.Thread | pthread_cancel() | interrupt ( ) member function of boost :: thread class | N/A | Chapter 9 |