SysV semaphore control operations

Daftar Isi

• semctl ID,SEMNUM,CMD,ARG

  Calls the System V IPC function semctl(2). You'll probably have to say

   use IPC::SysV;
   

  first to get the correct constant definitions. If CMD is IPC_STAT orGETALL, then ARG must be a variable that will hold the returnedsemid_ds structure or semaphore value array. Returns like ioctl:the undefined value for error, "0 but true" for zero, or the actualreturn value otherwise. The ARG must consist of a vector of nativeshort integers, which may be created with pack("s!",(0)x$nsem).See also SysV IPC in perlipc, IPC::SysV, IPC::Semaphoredocumentation.

  Portability issues: semctl in perlport.