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Why do I get an Easysoft licensing error stating the application was unable to create a semaphore?

This error occurs when the number of available semaphores is exceeded.

Semaphore errors usually indicate that all available semaphores have been used and there is no room to create a new structure. Easysoft semaphores can be identified as they are allocated in groups of 12. For example, 12, 24, 36, and so on.

To display existing semaphores, change to the root user and enter:

ipcs -sa

The resultant output is something like:

IPC status from /dev/kmem as of Thu Jan 24 10:34:58 2002
T ID KEY MODE OWNER GROUP CREATOR CGROUP NSEMS OTI
Semaphores:
s 0 0x002ab0df --ra------- root sys root sys 1 10:009
s 1 0x000018e5 --ra-ra-ra- root sys root sys 1 0:039
s 2 0x6f2a6e5b --ra-ra-ra- root sys root sys 24 12:256
s 3 0x792a93b8 --ra-ra-ra- root sys root sys 1 12:547
s 4 0x702a6e5b --ra-ra-ra- root sys root sys 12 11:339
s 15 0x6f2a6e55 --ra-ra-ra- root sys root sys 24 12:543
s 16 0x702a6e55 --ra-ra-ra- root sys root sys 12 12:546

To remove a semaphore, use:

ipcrm -s semaphore_id

For example:

ipcrm -s 15

This frees up the slot.