On 02/15/2015 09:28 AM, Eli Zaretskii wrote:
>> Date: Sun, 15 Feb 2015 09:04:01 -0800
>> From: Daniel Colascione <dancol@dancol.org>
>> CC: stephen_leake@stephe-leake.org, emacs-devel@gnu.org
>>
>> Modules provide an initialization function to Emacs: Emacs then
>> calls this initialization function with a pointer to a C structure
>> containing a table of function pointers. Modules call these function
>> pointers to do their work.
> 
> How will modules know which function in the table does what job?

Positionally, as fixed in the structure that defines the table.

struct {
  void (*func1)(int);
  void (*func2)(double);
  /* etc. */
}

This way, the ABI Emacs exports is explicit, and breaking it is unlikely
to happen accidentally.