<div>Todd<br></div><div><br></div><div>I just successfully compiled this program in MRtrix version 0.2.10. This, combined with the location of the error you're getting, suggests that your system is either missing the necessary header files to compile this program (not likely), or the required header files are not being found in the compilation process (more likely).</div>
<div><br></div><div>In file cmd/merge_tracks.cpp, try adding the following line near the top of the file (around line 27):</div><div>#include <unistd.h></div><div>The merge_tracks program uses code libraries that come with Linux to navigate and interrogate the HDD directory structure; addition of this line should hopefully inform the compiler where to find the relevant libraries. If this still doesn't fix the problem please let me know, as I can't reproduce the error at my end.</div>
<div><br></div><div>Best regards</div><div>Rob</div>