So I have finished reading an article here:
https://msdn.microsoft.com/en-us/library/ms809983.aspx
about why we have COM and how it lets us share code without worrying about name mangling of compilers or unicode/ascii issues or memory management in a language independent manner.
I have elsewhere read that COM isn't supposed by LINUX because COM basically uses the OS as the moderator for acquisition of these standardized objects. Shouldn't there be something similar in Linux? and if so, what is it?
On Linux you can run any program that accepts its input on standard input, and connect it, via a pipe, to any other program that generates its results on its standard output.
The simple, file and pipe-based input/output in POSIX predates MS-Windows by decades. And, as long as both sides of the pipe agree on the format of the data being interchanged, it doesn't matter which compiler was used to create each program (although, on Linux, there's pretty one de-factor compiler, so it's a moot point).
And by using a socket-pair, the pipe becomes bi-directional, so both processes can swap data with each other.
This is, generally, how processes interoperate on Linux:
1) A pipe, or a network socket, that connects the two processes together
2) An agreed, established standard for the format of the data exchanged between the two processes.
It is important to understand that there is no practical standard for all processes to use the same exact format for exchanging messages. The closest that would come to such a standard, I suppose, would be the remote procedure call, or RPC, standard that's used in some low-level protocols, like NFS, but, mostly, individual applications define and use a particular format that's tailored for them.
For example, the X Window System Protocol: http://www.x.org/releases/X11R7.7/doc/xproto/x11protocol.html -- this is a format definition of a protocol for communicating between an X server and an X client. Applications that are written to use this protocol (they'll typically use an intermediate library or a toolkit, actually) can establish a connection and use any X server that talks the same protocol, over a network connection or a local pipe.