The IMPORT and EXPORT keywords let you share data among the procedures in
a program without explicitly passing the data as parameters — in other words,
they provide a “hidden interface” between procedures.

PGM – EXP_IMP1

d Var1 S 5p 0 Export Inz(3)

c Var1 dsply r 1

c callb ‘EXP_IMP1’

c Var1 dsply r

c return

PGM – EXP_IMP1

d Var1 S 5p 0 Import

c Var1 dsply r 1

c z-add 77 Var1

c Var1 dsply r

c return

THEN USE
CRTRPGMOD OR PDM OPTION 15 TO CREATE MODULE
THEN
CRTPGM PGM(LIB/PGM_NAME) MODULE() ()