PLOCK(2-SVR4)       RISC/os Reference Manual        PLOCK(2-SVR4)



NAME
     plock - lock into memory or unlock process, text or data

SYNOPSIS
     #include <sys/lock.h>

     int plock(int op);

DESCRIPTION
     plock allows the calling process to lock into memory or
     unlock its text segment (text lock), its data segment (data
     lock), or both its text and data segments (process lock).
     Locked segments are immune to all routine swapping.  The
     effective user ID of the calling process must be super-user
     to use this call.  plock performs the function specified by
     op:

          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.

     plock fails and does not perform the requested operation if
     one or more of the following are true:

     EPERM          The effective user ID of the calling process
                    is not superuser.

     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 lock exists on
                    the calling process.

     EAGAIN         Not enough memory.

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




                        Printed 11/19/92                   Page 1

PLOCK(2-SVR4)       RISC/os Reference Manual        PLOCK(2-SVR4)



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.

NOTES
     memcntl is the preferred interface to process locking.
















































 Page 2                 Printed 11/19/92