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16.5. A Simple GNU/Linux Dynamic Module

As an appetizer for working with dynamic loadable modules, here is a minimal module written for the interface used by the loader in the preceding section:

#include <stdio.h>

int
run (const char *argument)
{
  printf ("Hello, %s!\n", argument);
  return 0;
}

Again, to compile on a GNU/Linux machine:

$ gcc -fPIC -c simple-module.c
$ gcc -shared -o simple-module.so

Having compiled both loader and module, a test run looks like this:

$ ./simple-loader simple-module World
Hello, World!
        => 0

If you have a GNU/Linux system, you should experiment with the simple examples from this chapter to get a feel for the relationship between a dynamic module loader and its modules—tweak the interface a little; try writing ...