OpenEuphoria

Re: Creating and using a .DLL/.SO?

• Posted by jeremy (admin) Dec 25, 2008
• 1122 views

How will this work when I want to load multiple dll/so files that have the same function names? For instance:

dbi_pgsql.so, dbi_mysql.so, dbi_sqlite.so, dbi_eds.so:

dbi_open(), dbi_query(), dbi_close()

In code, I could do something like:

public function dbi_load_driver(sequence name) 
   atom driver_id = open_dll("mod_" & name) 
   return { 
       driver_id, 
       define_c_func(driver_id, "dbi_open", ...), 
       ... 
   } 
end function 
 
public function dbi_open(driver, ...) 
    return c_func(driver[FUNC_DBI_OPEN], ...) 
end function 
 
... 

Thus, a Euphoria program could connect to multiple database servers/files at the same time, varrying, and have no idea what the actual underlying database would be. A common interface, loaded at runtime. The application could be extended for database support far beyond what the original author ever knew. Simply develop a new, conforming DBI driver and the application would be able to then access that database.

So, in this case, I would not want the contents of the mod_pgsql.so and mod_mysql.so automatically available to the runtime. I would think this type of thing would happen frequently. For instance, any type of pluggable module. Say you have a modular system to load a file: mod_text.so, mod_rtf.so, mod_html.so, mod_xml.so, etc... All of them would include a function called: open_file()... and would return some type of common data type for your application. I may want to open/parse html files, xml, rtf, etc... all at the same time, so all modules would be loaded, but all have the exact same function names.

Jeremy