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



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 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

ERRORS
     plock will fail and not perform the requested operation if
     one or more of the following are true:

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

     [EINVAL]                 op is equal to PROCLOCK and a pro-
                              cess 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 pro-
                              cess.



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



     [EAGAIN]                 Not enough memory.

SEE ALSO
     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.














































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