Calls the System V IPC function shmctl. You'll probably have to say
- use IPC::SysV;
first to get the correct constant definitions. If CMD is IPC_STAT
,
then ARG must be a variable that will hold the returned shmid_ds
structure. Returns like ioctl: undef for error; "0
but
true" for zero; and the actual return value otherwise.
See also SysV IPC in perlipc and IPC::SysV
documentation.
Portability issues: shmctl in perlport.