Programming Guides › Programming Guide for C › Directory API › Structures Used in the Sample Directory Application › How To Distinguish between Handle Types

How To Distinguish between Handle Types

Some functions, such as SmDirReleaseInstance(), may be passed either the directory instance handle or the directory entry (user) instance handle. The sample code provides a way you can distinguish the directory instance handle from the directory entry (user) instance handle.

Notice that nTag is the first field of both DirHandle_t and UserHandle_t. When SmDirInitDirInstance() is called, nTag is set to 0 in DirHandle_t. When SmDirInitUserInstance is called, nTag is set to 1 in UserHandle_t.

When a function that accepts either type of handle is called, the value of nTag is checked to see which type of handle is being passed.