Why Can't I Copy a `stringstream` Object in C ?

Why Copying Stringstream Is Prohibited

Copying stringstream objects is not permitted in C due to the privatization of their copy constructors. This applies to all stream types, including stringstream, istream, ostream, and iostream.

Streams are not mere containers that can be duplicated. They serve as conduits through which data flows, connecting a source to a sink. Unlike containers, streams do not hold data but rather facilitate its transmission.

Consider the analogy of a stream to a pipe that transports data. Creating a copy of a stream would be akin to creating an additional pipe connected to the same data source. However, since the data has already been consumed by the original stream, there is no new data to be received by the copy.

To illustrate:

int main() {
   std::stringstream s1("This is my string.");
   std::stringstream s2 = s1; // error, copying not allowed
}

In this example, attempting to copy s1 into s2 results in an error because it would create a duplicate connection to a data source that has already been exhausted.

While copying streams is prohibited, creating references to them is still permissible. This allows multiple code entities to access the same underlying data source without the need for duplication.

std::istream  copy_cin = std::cin; //error
std::istream & ref_cin = std::cin; //ok

Additionally, it is possible to create a new stream object that uses the same underlying buffer as an existing stream.

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