PLOCK(2)             INTERACTIVE UNIX System             PLOCK(2)



          NAME
               plock - lock process, text, or data in memory

          SYNOPSIS
               #include <sys/lock.h>

               int plock (op)
               int op;

          DESCRIPTION
               The plock system call allows the calling process to lock its
               text segment (text lock), its data segment (data lock), or
               both its text and data segments (process lock) into memory.
               Locked segments are immune to all routine swapping.  plock
               also allows these segments to be unlocked.  The effective
               user ID of the calling process must be super-user to use
               this call.  Op specifies the following:

                       PROCLOCK -    lock text and data segments into
                                     memory (process lock)

                       TXTLOCK -     lock text segment into memory (text
                                     lock)

                       DATLOCK -     lock data segment into memory (data
                                     lock)

                       UNLOCK -      remove locks

               The plock system call will fail and not perform the
               requested operation if one or more of the following is true:

               [EPERM]        The effective user ID of the calling process
                              is not super-user.

               [EINVAL]       Op is equal to PROCLOCK and a process lock, a
                              text lock, or a data lock already exists on
                              the calling process.

               [EINVAL]       Op is equal to TXTLOCK and a text lock or a
                              process lock already exists on the calling
                              process.

               [EINVAL]       Op is equal to DATLOCK and a data lock or a
                              process lock already exists on the calling
                              process.

               [EINVAL]       Op is equal to UNLOCK and no type of lock
                              exists on the calling process.

               [EAGAIN]       Not enough memory.

          SEE ALSO


          Rev. C Software Development Set                            Page 1

          PLOCK(2)             INTERACTIVE UNIX System             PLOCK(2)



               exec(2), exit(2), fork(2).

          DIAGNOSTICS
               Upon successful completion, a value of 0 is returned to the
               calling process.  Otherwise, a value of -1 is returned, and
               errno is set to indicate the error.

















































          Rev. C Software Development Set                            Page 2