model -- a gtk:tree-model object being searched
column -- an integer with the search column set by the gtk:tree-view-search-column function
key -- a key string to compare with
iter -- a gtk:tree-iter iterator pointing the row of model that should be compared with key
result -- false, if the row matches, true otherwise

A callback function used for checking whether a row in model matches a search key string entered by the user. Note the return value is reversed from what you would normally expect.