While running GMP-ECM with B1=11000000 and c=1302, it stopped with Exit status 15 and found no factors. The only place I have found the exit status values documented is the Linux Man page for gmp-ecm at
https://www.systutorials.com/docs/linux/man/1-gmp-ecm/. It doesn't show exit status 15.
Anyone know what this value means? I was running in quiet mode so no other indications.