c++ - Feed std::vector<unsigned char> from unsigned char * -

i have write piece of code:

unsigned char *buffer = ... ... std::vector<unsigned char> vec(buffer,128); 

this works feed vector after declaration (suppose vector field of class)

unsigned char *buffer = ... ... std::vector<unsigned char> vec; ... vec = vec(buffer,128) ??? 

i not know on last line. thing works resize vector memcpy. there better way?

well, move semantics, can do

vec = std::vector<unsigned char>(buffer, buffer + 128); 

if ruffles feathers, can use std::copy std::back_inserter:

vec.reserve(128); std::copy(buffer, buffer+128, std::back_inserter(vec)); 

another option use vector::assign.