10.7  External Solver Output and Log

The external solver’s output can be controlled using:

lp_set(SolverChannel, +(Stream))

Send output from SolverChannel to the ECLⁱPS^e I/O stream Stream.

lp_set(SolverChannel, -(Stream))

Stop sending output from SolverChannel to the ECLⁱPS^e I/O stream Stream.

SolverChannel is one of result_channel, error_channel, warning_channel, log_channel, and Stream is an ECLⁱPS^e stream identifier (e.g. output, or the result of an open/3 operation). By default, error_channel is directed to ECLⁱPS^e’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).