I'm talking about the configuration setting when making mex files. I have a case where compiling without it causes occasional random segmentation faults when the mex file is used. If integrity checks are enabled it seems to work. I would have expected to get an error even with integrity checks on (maybe just friendlier than a seg fault), but this is not the case. It runs flawlessly as .m or mex with integrity checks and seg faults without integrity checks.