some utilities of shared memory.
shmutil implements a mutli-reader-single-writer hashtable and ring queue in shared memory.
Features of hashtable:
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Support mutli-reader-single-writer operating hashtable concurrently, not support multi-writers operating hashtable at same time.
If you want to handle problem of multi processes writing the hashtable, please use cross-process lock(such as file-lock) utility to synchronize multiple processes.
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Note: the key size can not be longer than 96 bytes.
If you wish to support large key longer than 96 bytes, please change
_Q_HASHARR_KEYSIZEvalue inqlibc.h. -
Support LRU elimination while shm space is full.
Features of ring queue:
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Support single-reader-single-writer lock-free operating queue concurrently, and also provide locked version to handle multiple reader or multiple writer operating queue at same time.
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Its a FIFO queue. If shm space is full while pushing,
shmutilwill returnkErrNotEnoughSpaceerror.
Please refer to example directory for how to use it.
Some ideas are inspired from other open-source projects, thanks for MSEC, QCONF, libshmcache projects.