plock(2)                                                 plock(2)



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

     SYNOPSIS
          #include <sys/lock.h>

          int plock(op)
          int op;

     DESCRIPTION
          plock 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 seg-
          ments are immune to all routine swapping.  plock also allows
          these segments to be unlocked.  The effective user ID of the
          calling process must be superuser to use this call.  op
          specifies the following:

          PROCLOCK      lock text and data segments into memory (pro-
                        cess lock)

          TXTLOCK       lock text segment into memory (text lock)

          DATLOCK       lock data segment into memory (data lock)

          UNLOCK        remove locks

     RETURN VALUE
          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.

     ERRORS
          plock 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 superuser.

          [EAGAIN]       The system has temporarily exhausted its
                         available memory or swap space.

          [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



     April, 1990                                                     1

     plock(2)                                                 plock(2)



                         process.

          [EINVAL]       op is equal to UNLOCK and no type of lock ex-
                         ists on the calling process.

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
















































     2                                                     April, 1990