Server detection of client process termination

Abstract

A service provider for use in a client-server system which is capable of detecting the abnormal termination of a client process is disclosed. The service provider does not require a dedicated process for polling client processes in order to verify their status. Rather, a semaphore, which is used in conjunction with a shared memory segment for communication between a client process and the service provider, is initialized in such a manner that the operating system will automatically increment the semaphore in the event the client process is terminated. Thus, the semaphore will be incremented either when the client process deliberately increments the semaphore in order to notify the service provider that the client process has written data to a shared memory segment, or the semaphore will be incremented by the operating system in the event the client process terminates. A test flag is established in shared memory in order to differentiate whether the semaphore was incremented by the client process, or by the operating system. The client process will set the flag only when the client process increments the semaphore. Therefore, whenever the semaphore is incremented, the service provider will test the condition of the flag, and terminate resources allocated to the client process if the flag is not set.