Constructing std::regex from a char* slice, without copy

I'm working with some C++11 code, I have raw C character pointer (char const * const), and I want to make a std::regex from a specific section of it (a slice of the memory).

I could construct a std::string from the pointer's memory slice, and cause a heap allocation, but I'm hoping to avoid this.

The std::regex's constructor's second parameter is a set of regex bit flags, not a length to read.

Is there a good solution for this, given that I am trying to reduce memory copies?

The constructor can accept a char iterator, can that solve this?