Searches for an existing semaphore with the given name and returns its handle.

HANDLE OpenSemaphore(
    DWORD dwDesiredAccess,
    BOOLEAN bInheritHandle,
    LPCTSTR lpName
);

HANDLE RtOpenSemaphore(
    DWORD dwDesiredAccess,
    BOOLEAN bInheritHandle,
    LPCTSTR lpName
);

Parameters

dwDesiredAccess

Ignored.

bInheritHandle

Ignored.

lpName

Pointer to a null-terminated string that specifies the semaphore to open. Name comparisons are case sensitive.

Remarks

RtOpenSemaphore can also be used from a Windows application to obtain the handle of an iwin32 process.

OpenSemaphore enables multiple processes to open handles of the same semaphore object. The function succeeds only if a process already created the semaphore by using CreateSemaphore. The calling process can use the returned handle in any function that requires a handle to a semaphore object, such as the wait functions.

To close the handle, use CloseHandle. When the process terminates, the system automatically closes the handle. After the last handle closes, the semaphore object is destroyed.

Return Values

Handle to semaphore object

Success.

NULL

Failure. For extended error information, see GetLastError.

Requirements

Notes

• In the iwin32 API, OpenSemaphore and RtOpenSemaphore are synonyms.
• This function operates in the real-time portion of your application.
• The iwin32x API also includes an RtOpenSemaphore function that operates in the Windows portion of your application.

See Also

CloseHandle, CreateSemaphore, ReleaseSemaphore, iwin32 API, iwin32 Overview