The compound-file table of contents (CTOC) entry for the element does not have to exist prior to the call. mmioCFAddElement adds the entry if it does not exist. The mmioCFAddElement function writes the element to the end of the compound-file resource-group (CGRP) chunk. The user's buffer contains the element data.

This function is used when the element exists but is not contained in the RIFF compound file. If the element does not exist, use mmioOpen with the MMIO_CREATE flag to add a newly created element to the RIFF compound file. In that case the file name used with mmioOpen must contain the compound file and element name (that is, aaa.bnd+element).

The user is not required to use mmioCFAddElement to add an element to a RIFF compound file. However, one would need to replicate the following function that mmioCFAddElement provides.

• Seek to the start of the RIFF compound file.

• Descend to the BND chunk.

• Descend to the CGRP chunk.

• Seek to the end of the CGRP.

• mmioWrite to write all of the data.

• Ascend the CGRP to correct the size.

• Ascend the BND to correct the size.

• If the CTOC already exists, call mmioCFChangeEntry to update the data offset and size of the element.

• If not, call mmioCFAddEntry to add the CTOC entry.