B.3.3  Dynix/PTX Spin Lock Primitives

In Windows NT, the thread that acquires a spin lock must release the lock. Another thread cannot release the spin lock on behalf of the first thread. Variables of type lock_t should only be accessed by the following Dynix/PTX spin lock primitives (Further Readings on Streams, Reference 3):

·init_lock

·p_lock

·v_lock

These primitives are implemented as macros that call the kernel-mode spin lock functions.

init_lock

The init_lock function initializes a spin lock.

VOID

init_lock(

    IN lock_t *lockp

    );

Parameters

lockp

Points to the spin lock to be initialized.

p_lock

The p_lock function acquires a spin lock and returns the previous IRQL.

INT

p_lock(

    IN lock_t *lockp,

    IN INT ignored

    );

Parameters

lockp

Points to the spin lock to be acquired.

ignored

Ignored for Windows NT.

v_lock

The v_lock function releases a spin lock.

VOID

v_lock(

    IN lock_t *lockp,

    IN USHORT level

    );

Parameters

lockp

Points to the spin lock to be released.

level

Specifies the IRQL to restore.