Note: This problem was fixed in Matlab R2015a and newer, but was broken in Matlab R2013a/R2013b. Not sure about R2014a/R2014b.
Matlab R2013a/R2013b cannot handle uint64 seek offsets. However, Octave 3.6, 3.8, 4.0 can work with uint64 offsets.
offs = uint64(0); %or any number fid = fopen('test.dat'); fser = fseek(fid,offs,'bof');
fser will be -1 for Matlab R2013a/R2013b, 0 for octave