DosCreateSpinLock

Create a spinlock for multiprocessor serialisation.

Syntax

DosCreateSpinLock (pHandle)

Parameters

phandle (PHSPINLOCK)

A pointer to the spinlock handle that can be passed to DosAcquireSpinLock to acquire a spinlock and to DosReleaseSpinLock to release the spinlock.

Returns

ulrc (APIRET)

0 NO_ERROR

32804 ERROR_NO_MORE_HANDLES

Remarks

The device driver should protect access to critical resources using spinlocks. The device driver allocates spinlocks in the Init routine by calling DevHlp_CreateSpinLock. CreateSpinLock returns a handle for use by the device driver. This handle is passed to DevHlp_AcquireSpinLock and DevHlp_ReleaseSpinLock. The spinlock is freed by calling DevHlp_FreeSpinLock. The driver may request any number of spinlocks, as the spinlocks are represented by a very small data structure. Once created, the spinlocks never go away.

Example Code

// OS/2 adv srv 4 SMP spinlock
extern "C" {
            typedef ULONG HSPINLOCK;
            typedef HSPINLOCK FAR *PHSPINLOCK;
            APIRET APIENTRY DosCreateSpinLock(PHSPINLOCK pHandle);
            APIRET VOID DosAcquireSpinLock(HSPINLOCK Handle);
            APIRET VOID DosReleaseSpinLock(HSPINLOCK Handle);
            APIRET APIENTRY DosFreeSpinLock(HSPINLOCK Handle);
            };

class SpinLock {
        HSPINLOCK sl;
public:
        SpinLock() { DosCreateSpinLock(&sl); }
        ~SpinLock() { DosFreeSpinLock(sl); }
        void Request() {
                DosAcquireSpinLock(sl);
        }
        void Release() {
                DosReleaseSpinLock(sl);
        }

};

Related Functions

• DosAcquireSpinLock
• DosFreeSpinLock
• DosReleaseSpinLock