I've been experimenting with filename I/O using sockets, and found that there seems to be a difficulty when one writes to a socket before reading from it. For example this job writes a line to the "echo" port of a system, and wants to read it back from the same port.(Yes, the echo port is working on this system). :

filename echosock socket 'nber3.nber.org:7'; data; file echosock; put 'stuff to echo'; infile echosock; input; file log; put _infile_; run;

Even before the socket is opened, SAS generates an error message:

ERROR: The FILE and INFILE statements are out of proper order for update processing. The INFILE statement must be specified before the FILE statement.

Of course I am not doing UPDATE processing (AFAICT). The documentation for sockets is at http://tinyurl.com/mz35oz but it doesn't mention anything about reading and writing to the same socket. I didn't realize it was allowed until I read the Proceedings paper at http://tinyurl.com/leqygc and while I can get those examples to work, they always read a banner before writing to the socket. I have a feeling the error message may just be overzealous error checking.

Daniel Feenberg 617-588-0343 feenberg@gmail.com