semaphore communication

Semaphore is currently used in multi-threaded environments, the operating system semaphore is a very important concept, in the process of control has been applied. The semaphore of the Java Concurrency Library makes it easy to control the semaphore, Semaphore can control the

() T2.start () T3.start () T4.start ()3. Signal Volume semaphore: from Import Semaphore semaphore Semaphore---Essence is a lock ====== control the number of simultaneous processes (more processes can be opened in the background) process Pool ----number of processes running concurrently () 4.-Timers Timer:# From thre

Java. util. concurrent package source code reading 17 semaphores Semaphore and semaphores semaphore Anyone who has learned about the operating system knows the Semaphore. In the java. util. concurrent package, there is also a Semaphore implementation: Semaphore. From the per

Thread synchronization-semaphore (semaphore)Rethinking the problems of producers and consumersIn real life, there is only a commodity. Consumers will be able to consume, that's fine.But the production of producers is not unlimited. For example, the warehouse is limited, the raw materials are limited, production indicators are limited by consumption indicators and so on. In order to further solve the problem

A count semaphore. Conceptually, semaphores maintain a set of licenses. If necessary, block each acquire () before the license is available, and then obtain the license. Each release () adds a license that may release a blocked fetch. However, instead of using the actual license object, Semaphore only counts the number of available licenses and takes action accordingly. The thread that gets the

created by case) a named semaphore Sem_init ()-Initializes a semaphore structure (belonging to the internal structure of the caller, so it is not a named semaphore) Sem_close ()-Terminates the connection of an open semaphore Sem_unlink ()-Terminates an open semaphore con

* * Producer/consumer model * given warehouse volume (N) * Generator generated product warehousing * Consumers take out product consumption from warehouse * When the warehouse is full, the producer cannot continue to generate * The customer cannot

　　Semaphore can control how many times a shared resource can be accessed concurrently, to maintain the number of threads currently accessing a shared resource, and to provide a synchronization mechanism. For example, control the number of concurrent accesses allowed for a file.For example, there are 100 machines in the Internet bar, so the maximum can only provide 100 people at the same time the Internet, when the 101th guest, it is necessary to wait,

0. Signal VolumeThe semaphore under Linux is slightly different from the amount of semaphores under Windows.WindowsThe semaphore under Windows has a maximum value and an initial value, and the initial and maximum values can be different. And the semaphore under Windows is a "kernel object" that can be accessed throughout the OS.LinuxThe

SemaphoreThe semaphore is divided into single-valued and multi-valued two, which can only be obtained by one thread, the latter of which may be obtained by several threads.Semaphore implementation of the function is similar to the toilet has 5 pits, if there are 10 people to the toilet, then at the same time only how many people to go to the toilet? At the same time only 5 people can occupy, when any one of the 5 people out of the way, one of the othe

1: Code #include #include #include #include #include #include #define MAX_SEMAPHORES 3union semun{ int val; /* value for SETVAL */ struct semid_ds *buf; /* buffer for IPC_STAT, IPC_SET */ unsigned short

1. It is not an IPC Mechanism. It provides synchronization between different processes or between different threads of the same process! 2. type: . binary signal: If the value is 0 or, there is a resource available. If the value is 0, it indicates

The Code comes from the book CD, "Principles and Applications of the embedded operating system ucoⅱ" Instance 1 semaphore # Include "des. H" # Define task_stk_size 512 // Task Stack Length OS _stk starttaskstk [task_stk_size]; // defines the task stack area.OS _stk mytaskstk [task_stk_size];OS _stk youtaskstk [task_stk_size];OS _stk hertaskstk [task_stk_size]; Int16s key; // The key used to exit ucos_iiChar * S1 = "mytask ";Char * S2 = "youtask "; Int