It's actually easier that it seems, you only have to use the sort()
method. Take a look at Octave's doxygen documentation for ColumnVector
:
#include <octave/oct.h>
DEFUN_DLD (foo, args, , "sort an array")
{
ColumnVector unsorted = args(0).vector_value ();
ColumnVector sorted = unsorted.sort ();
return octave_value (sorted);
}