Sets a new value for an existing meta data item or adds a new item. Meta data tag names can be something like e.g. "comment". Supplying NULL for the value will unset an existing value.
preset name
meta data item name
new value
TRUE for success, FALSE if e.g. there is no preset with that name
Sets a new value for an existing meta data item or adds a new item. Meta data tag names can be something like e.g. "comment". Supplying NULL for the value will unset an existing value.