The external solver’s output can be controlled using:
SolverChannel is one of result_channel, error_channel, warning_channel, log_channel, and Stream is an ECLiPSe stream identifier (e.g. output, or the result of an open/3 operation). By default, error_channel is directed to ECLiPSe’s error stream, warning_channel to warning_output stream, while result_channel and log_channel are suppressed. To see the output on these channels, do for instance
:- lp_set(result_channel, +output), lp_set(log_channel, +log_output).
Similarly, to create a log file:
:- open("mylog.log", write, logstream), lp_set(log_channel, +logstream).
and to stop logging:
:- lp_set(log_channel, -logstream), close(logstream).