How should size( "foo" ) behave if "foo" is a directory? 1) Throw. The function should be renamed file_size(). 2) Return 0. Directories don't strictly speaking have a size. 3) Return the number of entries in the directory. Directories are really just containers; so of course they have a size. (1) and (3) seem most attractive to me; (2) seems useless for directories, and probably misleading. The problem with (3) is that for many (most?) operating systems the implementation would have to iterate over the directory to get a count, and this difference in complexity compared to getting the size of a file (which is usually constant complexity) could be pretty surprising. I'm inclined to go with (1), naming the function "file_size", and then add a function later to get the number of entries in a directory. But only if there is enough demand. I don't want to clutter up the library with a lot of seldom used functions that can be trivially written as user code. Thoughts? --Beman