On Fri, 1 Jun 2007, Adrian F. Clark wrote:

The easiest solution is to put

fflush (stdout);

after each printf() invocation -- or equivalent in other languages. Other solutions tend to be less portable.

Thanks, that worked a treat. For the archives, the language is Perl, and, with a bit of manpage searching (once you'd clued me in that the word "fflush" was relevant,) I found out the "equivalent" is to put

use IO::File ; autoflush STDOUT 1 ;

at the start of the program.