In the fastmatch package, version 1.1-0, there is a C function called "ctapply_", with a trailing underscore. However, the NAMESPACE's call to useDynLib refers to "ctapply", without the trailing underscore. % grep ctapply NAMESPACE {R,src}/* NAMESPACE:useDynLib(fastmatch, C_fmatch = fmatch, C_ctapply = ctapply, C_coalesce = coalesce, C_append = append, mk_hash, get_table, get_values) NAMESPACE:export(fmatch, fmatch.hash, ctapply, coalesce, "%fin%") R/ctapply.R:ctapply <- function(X, INDEX, FUN, ..., MERGE=c) .External(C_ctapply, parent.frame(), X, INDEX, FUN, MERGE, ...) src/ctapply.c:SEXP ctapply_(SEXP args) { src/ctapply.c: see ctapply(x, y, identity). It should be uncommon, though "Writing R Extensions" mentions, section 5.2, footnote 121, that .C and .Fortran interpret their first argument as the name of the object file symbol "possibly after some platform-specific translation, e.g. adding leading or trailing underscores". Should useDynLib use the underscored name? The code doesn't seem "platform-specific". What are the rules concerning added underscores (or capitalization?) that R uses? Bill Dunlap TIBCO Software wdunlap tibco.com [[alternative HTML version deleted]]