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 element name itself can not be modified.) mmioCFChangeEntry updates the compound-file CTOC entry with the information contained MMCTOCENTRY structure. If the compression technique is changed, the ulUncompressBytes field of the MMCTOCENTRY structure must also be changed. When the compression technique is NULL, the ulUncompressBytes field must be the size in bytes of the element when it is uncompressed. Consider calling mmioCFFindEntry to fill in the MMCTOCENTRY structure prior to calling this function.