Spurious Wakeup
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Spurious Wakeup
A spurious wakeup happens when a thread wakes up from waiting on a condition variable that's been signaled, only to discover that the condition it was waiting for isn't satisfied. It's called spurious because the thread has seemingly been awakened for no reason. But spurious wakeup don't happen for no reason: they usually happen because, in between the time when the condition variable was signaled and when the waiting thread finally ran, another thread ran and changed the condition. There was a race condition A race condition or race hazard is the condition of an electronics, software, or other system where the system's substantive behavior is dependent on the sequence or timing of other uncontrollable events. It becomes a bug when one or more of t ... between the threads, with the typical result that sometimes, the thread waking up on the condition variable runs first, winning the race, and sometimes it runs second, losing the race. On many systems, especially multiprocess ...
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Condition Variable
In concurrent programming, a monitor is a synchronization construct that allows threads to have both mutual exclusion and the ability to wait (block) for a certain condition to become false. Monitors also have a mechanism for signaling other threads that their condition has been met. A monitor consists of a mutex (lock) object and condition variables. A condition variable essentially is a container of threads that are waiting for a certain condition. Monitors provide a mechanism for threads to temporarily give up exclusive access in order to wait for some condition to be met, before regaining exclusive access and resuming their task. Another definition of monitor is a thread-safe class, object, or module that wraps around a mutex in order to safely allow access to a method or variable by more than one thread. The defining characteristic of a monitor is that its methods are executed with mutual exclusion: At each point in time, at most one thread may be executing any of its ...
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Race Condition
A race condition or race hazard is the condition of an electronics, software, or other system where the system's substantive behavior is dependent on the sequence or timing of other uncontrollable events. It becomes a bug when one or more of the possible behaviors is undesirable. The term ''race condition'' was already in use by 1954, for example in David A. Huffman's doctoral thesis "The synthesis of sequential switching circuits". Race conditions can occur especially in logic circuits, multithreaded, or distributed Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ... software programs. In electronics A typical example of a race condition may occur when a logic gate combines signals that have traveled along different paths from the same source. The inputs to the gate can chan ...
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Oracle Corporation
Oracle Corporation is an American multinational computer technology corporation headquartered in Austin, Texas. In 2020, Oracle was the third-largest software company in the world by revenue and market capitalization. The company sells database software and technology (particularly its own brands), cloud engineered systems, and enterprise software products, such as enterprise resource planning (ERP) software, human capital management (HCM) software, customer relationship management (CRM) software (also known as customer experience), enterprise performance management (EPM) software, and supply chain management (SCM) software. History Larry Ellison co-founded Oracle Corporation in 1977 with Bob Miner and Ed Oates under the name Software Development Laboratories (SDL). Ellison took inspiration from the 1970 paper written by Edgar F. Codd on relational database management systems ( RDBMS) named "A Relational Model of Data for Large Shared Data Banks." He heard about the ...
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The Open Group
The Open Group is a global consortium that seeks to "enable the achievement of business objectives" by developing "open, vendor-neutral technology standards and certifications." It has over 840 member organizations and provides a number of services, including strategy, management, innovation and research, standards, certification, and test development. It was established in 1996 when X/Open merged with the Open Software Foundation. The Open Group is the certifying body for the UNIX trademark, and publishes the Single UNIX Specification technical standard, which extends the POSIX standards. The Open Group also develops and manages the TOGAF® standard, which is an industry standard enterprise architecture framework. Members The over 840 members include a range of technology vendors and buyers as well as government agencies, including, for example, Capgemini, Fujitsu, HPE, Orbus Software, IBM, Huawei, Philips, the U.S. Department of Defense, and NASA. There is no obligation on ...
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C POSIX Library
The C POSIX library is a specification of a C standard library for POSIX systems. It was developed at the same time as the ANSI C standard. Some effort was made to make POSIX compatible with standard C ANSI C, ISO C, and Standard C are successive standards for the C programming language published by the American National Standards Institute (ANSI) and ISO/IEC JTC 1/SC 22/WG 14 of the International Organization for Standardization (ISO) and the ...; POSIX includes additional functions to those introduced in standard C. C POSIX library header files References Official List of headers in the POSIX library on opengroup.org* Further reading * {{CProLang POSIX ...
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