hi I am working on my bitpacking implementation and want to use STL bitset to store the bits I have examined the code of the bitset the data is stored in an array of unsigned long s I have 2 questions 1. Is it guaranteed that there won t be any additional variables in other STL implementations ? So i could simple do a reinterpret_cast on the pointer to send the bitpack over the network. 2. I miss the possibility to set n bits of a int at position idx in the bitset e.g.: for(i=0;i<n;i++) m.set(idx+i,value&(1<<i); is there a similar feature? what i could think of is a second bitset secondset = std::bitset<nbits>(value); firstset |= (secondset << idx); but I would rather prefer the first implementation since my bitsets will be around 150-300 bytes alrge == 2400 bits

It would need to store atleast the size and the actual data. Sending it over the network like that is a really bad idea; the bit-data is almost certainly allocated dynamically. All you'll get on the other side is a pointer to who-knows-where.

I prefer boost::dynamic_bitset if you need bitsets of varying sizes. It has functions allowing you to retrieve blocks of bits out of it as ulong or something. You could pack these into a buffer and send them. If your number of bits is static and you need to send it around like that I might prefer just using a struct with a bitfield inside.

i already thought about the bitfield but unfortunatly the data isn t static
i have aready written a little bitset maybe i just refine it a bit

thx

Ah, boost's dynamic bitset was what I was thinking of. I've never actually used the standard one. I didn't relieze it was static (Though... well. Duh. ...)