On 26 January 2016 at 09:13, Marius Miknis wrote: > Hi Marc, > > Thanks for such a quick reply, I appreciate it. > > Yes I am trying to speed up my testing in debug as working with point clouds of +600,000 points stored in vectors is really really slow, thus using _ MyFirst and _MyLast removes all the dereferencing/accessing overheads as I work directly with pointers and can just increment pointer addresses, plus even if the vector gets resized _ MyFirst and _MyLast are not affected. We don't provide direct access to members like that and never will. > I did look through the stl_vector.h but it sadly seems that I can not use ._M_impl._M_start. I am aware that compiler will remove all the overheads in release but currently in debugging I need a fast way to access and move through the vector. GCC doesn't have "release" and "debug". Compile with -Og and you can still debug the result easily, but a lot of the abstraction penalty is removed. Or you could compile with -fno-access-control but I don't recommend it. I am surprised that when accessing 600000+ points you will even notice the cost of doing v.data() and v.data+v.size() once to calculate those pointers each time the vector is modified. It certainly shouldn't be "really really slow".
