c-treeDB API API for C

ctdbGetFieldHandle

Retrieve a Field Handle.

Declaration

CTHANDLE ctdbGetFieldHandle(CTHANDLE Handle)

Description

ctdbGetFieldHandle() retrieves a Field Handle. This function can be used to test if a handle is really a field handle. For example, assume a function should take a field handle, but inside the function you cast the CTHANDLE type to the field CTDFIELD structure. For safety, it is a good idea to make sure that the handle is really a field handle as shown in the example below. Another minor reason for this call is to perform a ctdbSWTCREEI() call.

CTBOOL IsFieldNumeric(CTHANDLE hField)

{

CTBOOL Retval = FALSE;

pCTDBFIELD pField = (pCTDBFIELD)ctdbGetFieldHandle(hField);

if (!pField)

{

printf("Error: hField is not a field handle");

}

...

return Retval;

}

To allocate a field handle, use ctdbAllocField().

Handle [in] may be a field handle, an index handle, or a segment handle.

Returns

ctdbGetFieldHandle() returns a field handle on success or NULL on error.