semctl
- semctl ID,SEMNUM,CMD,ARG
Calls the System V IPC function
semctl
. You'll probably have to sayuse IPC::SysV;
first to get the correct constant definitions. If CMD is IPC_STAT or GETALL, then ARG must be a variable which will hold the returned semid_ds structure or semaphore value array. Returns like
ioctl
: the undefined value for error, "0 but true
" for zero, or the actual return value otherwise. The ARG must consist of a vector of native short integers, which may be created withpack("s!",(0)x$nsem)
. See also "SysV IPC" in perlipc,IPC::SysV
,IPC::Semaphore
documentation.