return value of a rpg program

hi,

is it possible in rpg to return a value from a program. i don't mean to
get a return value of a procedure.

i like to do something in perl like this:

$myvar = `system myrpgprogram`;

but i don't know how i should define my prototype in the rpg program.
the rpg program name is BS_SUBS. it tried it like this: 

DMain             PR            10A   EXTPGM('BS_SUBS') 
D  subname                      10A                     
D  sublib                       10A                     
 *                                                      
 *Entry list (parameter)                                
DMain             PI            10A                     
D  subname                      10A                     
D  sublib                       10A                     

but it says that a return value is not supported with EXTPGM key word.

thanx in advance for any help.

mk