Lock (computer Science) - Language Support

Language Support

See also: Barrier (computer science)

Language support for locking depends on the language used:

  • There is no API to handle mutexes in the ISO/IEC standard for C. The current ISO C++ standard, C++11, supports threading facilities. The OpenMP standard is supported by some compilers, and this provides critical sections to be specified using pragmas. The POSIX pthread API provides lock support. Visual C++ allows adding the synchronize attribute in the code to mark methods that must be synchronized, but this is specific to "COM objects" in the Windows architecture and Visual C++ compiler. C and C++ can easily access any native operating system locking features.
  • Java provides the keyword synchronized to put locks on blocks of code, methods or objects and libraries featuring concurrency-safe data structures.
  • In the C# programming language, the lock keyword can be used to ensure that a thread has exclusive access to a certain resource.
  • VB.NET provides a SyncLock keyword for the same purpose of C#'s lock keyword.
  • Python does not provide a lock keyword, but it is possible to use a lower level mutex mechanism to acquire or release a lock.
  • Ruby also doesn't provide a keyword for synchronization, but it is possible to use an explicit low level mutex object.
  • In x86 Assembly, the LOCK prefix prevents another processor from doing anything in the middle of certain operations: it guarantees atomicity.
  • Objective-C provides the keyword "@synchronized" to put locks on blocks of code and also provides the classes NSLock, NSRecursiveLock, and NSConditionLock along with the NSLocking protocol for locking as well.
  • Ada is probably worth looking at too for a comprehensive overview, with its protected objects and rendezvous.

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