man mplist_set () - Set the first property in a property list.
NAME
mplist_set - Set the first property in a property list.
SYNOPSIS
MPlist* mplist_set (MPlist * plist, MSymbol key, void * val)
DESCRIPTION
The mplist_set() function sets the key and the value of the first property in property list plist to key and value, respectively. See the documentation of mplist_add() for the restriction on key and val.
RETURN VALUE
If the operation was successful, mplist_set() returns plist. Otherwise, it returns NULL.