c++ Data serialization from templated class

I have a situation where I want to define a templated class which is able to get several different base types, like int, char array, data structure or a string. I want then to serialize and transmit the data using a method which accepts a pointer to array of chars and a length parameters.

sendData(const void *, size_t);

template <typename T>
T myClass(T data)
{
   // cast data to char array; calculate the length if not given
   sendData(data, length);
}

What is the best way to cast the the data parameter and calculate the size? Is template specialization the best option to deal with a case where we only expect to have predefined list of data types for the template? I am looking for a solution using native C++ and no external serialization libraries, and also avoiding reinterpret_cast. Can anyone provide me basic implementation example?

And on the receiver side, is there a way how the receiver can determine and validate that the data received have the expected type, before doing the deserialization?