A stream is a path for data movement. In this case, a stream is a path for output to a named destination. Every ABL procedure has one unnamed default output stream that writes data to the screen. The OUTPUT TO statement is your tool for redirecting the default stream to another destination. Once you use OUTPUT TO to change the output destination in a procedure, the output goes to that destination until you close it with the OUTPUT CLOSE statement, or until you name a new output destination.

This is a partial syntax for the OUTPUT TO statement:

OUTPUT [ STREAM stream | STREAM-HANDLE handle ] 
  TO { PRINTER | opsys-file | opsys-device }
  [ PAGED ]

OUTPUT [ STREAM stream | STREAM-HANDLE handle ] CLOSE