Question: I've came across a piece of C code (allegedly - the file has .c suffix).

It has a bunch of functions defined like so:

```
do_stuff
{
    // some stuff
}

do_other_stuff
{
   // some more stuff
}

```

There is no `#define do_stuff do_stuff()` in the code, neither an `#include` of any external file.

The code is run on some SDS relay device.

What is that? From the surrounding code and the way they are called, I assume they have `void` return type and no arguments, but what's up with the syntax?

Is this a thing in C, or some special C dialect?

Answer: 
While functions are allowed to omit the return type (defaults to `int`), they're not allowed to omit empty parentheses. Either it's a superset of C, or (more likely) they're actually macro definitions. Otherwise, it's not valid C.
Maybe this is not you case but I came upon this question

[Call function with arguments without parenthesis in C?](https://stackoverflow.com/questions/18348620/call-function-with-arguments-without-parenthesis-in-c)

Maybe it is related to the code you have. Either way it is an example of that kind of syntax in `C`.