The Cross-Platform xBase.
Version 3.0
       Harbour codeblock demonstration.
$ hbrun codebl.prg
        23
        42
        42
        15
        15         15
        14         15
        42         42
        14         42
        42         42
        14         42
         1          1
         3          3
         5          5
         6          6
         7          7
         9          9
        11         11
⋮
       100        100
Test for variables passed by reference in a codeblock
        42
        42
Test for indirect detaching of local variables
         2          2
         3          3
       200        200
       300        300
         4          4
Test for codeblock parameter passed by reference
lSomeVar value in Clipper .T. = .T.
Printed value in Clipper  .T. = .F.
lSomeVar value in Clipper .F. = .F.
Printed value in Clipper  .T. = .F.
2nd test for codeblock parameter passed by reference
lSomeVar value in Clipper .T. = .T.
Printed value in Clipper  .F. = .F.
lSomeVar value in Clipper .F. = .F.
Printed value in Clipper  .F. = .F.
To learn how to build/run this example, see this page.