[Boost-users] [array] with variable size

Hello, I have a third-party library that gives me a number N of doubles, then expects from me a double* to an array where it will set N elements This would have happen many times and N is variable, so I wish not to reallocate the array each time. I know however N is maxed at some value Nmax like 50. I thought of using a array that would be allocated once, then perhaps have a wrapper around it so that only N elements of it can be accessed. This seems to be a usual idiom, are there ready implementations? Regards,