C/C++ Endianness and tcp sockets

Question

I have a general conceptual question about endianness and how it affects tcp socket communication with C/C++. Here's an example:

You have two servers that are communicating with tcp sockets and one uses big endian and the other little endian. If you send an integer, over the socket, from one server to the other, I understand that the byte ordering is reversed and the integer will not print what is expected. Correct? I saw somewhere (I can't find where anymore) that if you send a char over the socket endianness doesn't change the value and it prints as expected. Is this correct? If so, why? I feel like I've done this before in the past, but I could be delusional.

Could anybody clear this up for me?

Thanks.

Edit: Is it because char is only 1 byte?

Answer 1

Think about the size of each data type.

An integer is typically four bytes, which you can think of as four individual bytes side by side. The endianness of an architecture determines whether the most significant byte is the first of the four bytes, or the last. A char, however, is only one byte. As I understand it, endianness does not affect the order of the bits in each byte (see the image on Wikipedia's page on Endianness).

A char, however, is only one byte, so there's no alternative order (assuming that I am correct that bits are not modified by endianness).

If you send a char over a socket, it will be one byte on both machines. If you send an int over a socket, since it's four bytes, it's possible that one machine will interpret the bytes in a different order than the other, according to the endianness. You should set up a simple way to test this and get back with some results!