RtkReleaseSemaphore

RtkReleaseSemaphore increases the count of the specified semaphore object by a specified amount.

Syntax

BOOL RtkReleaseSemaphore(
    RTSSINST RtssInst,
    PULONG pErrorCode,
    HANDLE hSemaphore,
    LONG lReleaseCount,
    PLONG lpPreviousCount
);

Parameters

RtssInst

An RTSSINST value returned from a call to RtkRtssAttach.

pErrorCode

A pointer to a location where additional error information may be returned. This location need not be defined; the user may pass a NULL value. If defined, this location is set to NULL if no error occurred.

hSemaphore

The semaphore object. RtkCreateSemaphore or RtkOpenSemaphore returns this handle.

lReleaseCount

The amount by which the semaphore object's current count is to be increased. The value must be greater than zero. If the specified amount would cause the semaphore's count to exceed the maximum count that was specified when the semaphore was created, the count is not changed and the function returns FALSE.

lpPreviousCount

A pointer to a 32-bit variable receives the previous count for the semaphore. This parameter can be NULL if the previous count is not required.

Return Values

TRUE if the function succeeds, FALSE if the function fails

Remarks

The state of a semaphore object is signaled when its count is greater than zero and non-signaled when its count is equal to zero. The process that calls RtkCreateSemaphore specifies the semaphore's initial count. Each time a waiting thread is released because of the semaphore's signaled state, the count of the semaphore is decreased by one.

Typically, an application uses a semaphore to limit the number of threads using a resource. Before a thread uses the resource, it specifies the semaphore handle in a call to one of the wait functions. When the wait function returns, it decreases the semaphore's count by one. When the thread has finished using the resource, it calls RtkReleaseSemaphore to increase the semaphore's count by one.

Another use of RtkReleaseSemaphore is during an application's initialization. The application can create a semaphore with an initial count of zero. This sets the semaphore's state to non-signaled and blocks all threads from accessing the protected resource. When the application finishes its initialization, it uses RtkReleaseSemaphore to increase the count to its maximum value, to permit normal access to the protected resource.

Requirements

Header	Rtkapi.h
Library	rtx_rtk.lib