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Top Forums Programming shared memory read/write using threads Post 302206739 by kumars on Wednesday 18th of June 2008 10:03:03 AM
Old 06-18-2008
shared memory read/write using threads

I am looking for C program source code. Could you please help me in finding the source code required mentioned below.

program to create multiple threads (one master thread and rest worker threads) and using the threads write into and read from shared memory


Restrictions:

Only one thread should be able to read at any instant of time into shared memory region.

Only one thread should be able to write at any instant of time into shared memory region.

Worker threads should inform the master thread after every read and write operation.

Master thread inform the worker thread (which is waiting to acquire shared memory region) that read or write operation is successful and it can acquire the memory for either reading and writing operations.
 

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pthread_rwlockattr_getpshared(3C)										 pthread_rwlockattr_getpshared(3C)

NAME
pthread_rwlockattr_getpshared, pthread_rwlockattr_setpshared - get or set process-shared attribute of read-write lock attributes object SYNOPSIS
cc -mt [ flag... ] file... -lpthread [ library... ] #include <pthread.h> int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *restrict attr, int *restrict pshared); int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr, int pshared); The process-shared attribute is set to PTHREAD_PROCESS_SHARED to permit a read-write lock to be operated upon by any thread that has access to the memory where the read-write lock is allocated, even if the read-write lock is allocated in memory that is shared by multiple processes. If the process-shared attribute is PTHREAD_PROCESS_PRIVATE, the read-write lock will only be operated upon by threads created within the same process as the thread that initialised the read-write lock; if threads of differing processes attempt to operate on such a read-write lock, the behaviour is undefined. The default value of the process-shared attribute is PTHREAD_PROCESS_PRIVATE. The pthread_rwlockattr_getpshared() function obtains the value of the process-shared attribute from the initialised attributes object ref- erenced by attr. The pthread_rwlockattr_setpshared() function is used to set the process-shared attribute in an initialised attributes object referenced by attr. If successful, the pthread_rwlockattr_setpshared() function returns 0. Otherwise, an error number is returned to indicate the error. Upon successful completion, the pthread_rwlockattr_getpshared() returns 0 and stores the value of the process-shared attribute of attr into the object referenced by the pshared parameter. Otherwise an error number is returned to indicate the error. The pthread_rwlockattr_getpshared() and pthread_rwlockattr_setpshared() functions will fail if: EINVAL The value specified by attr or pshared is invalid. See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ pthread_rwlock_init(3C), pthread_rwlock_rdlock(3C), pthread_rwlock_unlock(3C), pthread_rwlock_wrlock(3C), pthread_rwlockattr_init(3C), attributes(5), standards(5) 23 Mar 2005 pthread_rwlockattr_getpshared(3C)
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