I got what you said (and thanks in advance for helping me).
I had a look into the template. The block size is set, by default, to unsigned long (32 bytes). I tried to set the block size to unsigned char (1byte) by using the template syntax (it accepts only unsigned integer data types instead of the default block size) but the output of the function sizeof still is 32 bytes allocation. I was wondering if it is just a matter of "wrong"...

I am designing an application in which I need to deal with many different variables in which different sequences of bits are stored. I have very strict memory requirements so I decided to use the boost::dynamic_ bitset data type which works very well in my scenario as I need to dynamically allocate/deallocate/resize the variables.

The only problem is that I am not able to change the size of the blocks in which the dynamic_bitsets are...