semmnu
semmnu defines the maximum number of processes that can
have undo operations pending on any given IPC semaphore on the
system.
1
nproc-4
30
Specify integer value. For more information, see Specifying Parameter Values.
An undo is a special, optional, flag in a semaphore operation which causes that operation to be undone if the process which invoked it terminates (see HP-UX Reference entry semop(2) ) for more information about semaphore undo operations).
semmnu specifies the maximum number of processes that can
have undo operations pending on a given semaphore. It determines the
size of the sem_undo structure.
A semop() system call using the SEM_UNDO flag
returns an ENOSPC error if this limit is exceeded.
semmnu determines the size of the structure
sem_undo, which in turn contains the substructure
dimensioned by semume.
semmnu equal to
(nproc -4) because that is the largest number of
processes in the system that could use semaphores
simultaneously.