Passing Parameters in Powerbuilder

There are 2 ways of passing parameters from one window to another window
First:

//1st window                   >>>> 2nd Window 
message.of_setstringparm       >>>> message.of_getstringparm
message.of_setdoubleparm       >>>> message.of_getdoubleparm
message.of_setpowerobjectparm  >>>> message.of_getpowerobjectparm

Second:

//1st window                         >>>> 2nd Window
closewithreturn(window, 'string')    >>>> message.stringparm
closewithreturn(window, powerobject) >>>> message.powerobjectparm