The identifier for the entry is the element name, which is appended to the end of the MMCTOCENTRY structure passed in the pmmctocentry parameter. The CTOC entry is marked as deleted by setting the ulMedType field to FOURCC_DEL. The actual element data remains in place. To remove data that was previously marked for deletion, use mmioCFCopy. The result will be a compressed file with all those elements marked for deletion physically removed.