Did you know that you can run the compiler from sources specified in stdin?  Here’s an example:

// m.c
#include <stdio.h>

int main()
    int x = 3;
    printf("%d\n", x);
    return 0;

You have to specify the language for the code explicitly, since that can’t be inferred from the filename when that file data is coming from stdin:

$ cat m.c | clang -g -x c - -o f
$ ./f

This fact came up in conversation the other day. The result is something that is completely undebuggable, but you can do it! I’m curious if there’s actually a use case for this?