C++ read the whole file in buffer

What is a good approach to read the whole file content in a buffer for C++?

While in plain C I could use fopen(), fseek(), fread() function combination and read the whole file to a buffer, is it still a good idea to use the same for C++? If yes, then how could I use RAII approach while opening, allocating memory for buffer, reading and reading file content to buffer.

Should I create some wrapper class for the buffer, which deallocates memory (allocated for buffer) in it's destructor, and the same wrapper for file handling?

There's no need for wrapper classes for very basic functionality:

std::ifstream file("myfile", std::ios::binary | std::ios::ate);
std::streamsize size = file.tellg();
file.seekg(0, std::ios::beg);

std::vector<char> buffer(size);
if (file.read(buffer.data(), size))
{
    /* worked! */
}

You can access the contents of a file with a input file stream std::ifstream, then you can use std::istreambuf_iterator to iterate over the contents of the ifstream,

std::string
getFileContent(const std::string& path)
{
  std::ifstream file(path);
  std::string content((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>());

  return content;
}

In this case im using the iterator to build a new string using the contents of the ifstream, the std::istreambuf_iterator<char>(file) creates an iterator to the begining of the ifstream, and std::istreambuf_iterator<char>() is a default-constructed iterator that indicate the special state "end-of-stream" which you will get when the first iterator reach the end of the contents.

Something I have in most of my programs:

/** Read file into string. */
inline std::string slurp (const std::string& path) {
  std::ostringstream buf; 
  std::ifstream input (path.c_str()); 
  buf << input.rdbuf(); 
  return buf.str();
}

Can be placed in a header.
I think I have found it here: https://stackoverflow.com/a/116220/257568