in reply to Re^2: YASWI "Prolog System Error: Thread 1"
in thread YASWI "Prolog System Error: Thread 1"

IIRC, the right combination is... 
swi_init(qw(-nosignals -g true))

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The -g true part serves to silence the welcome banner generated by default by the Prolog engine.

In Section Seekers of Perl Wisdom