Subroutines, Macros
2.3 Subroutines with parameter transfer (PROC, VAR)
Job planning
Programming Manual, 03/2006 Edition, 6FC5398-2BP10-1BA0
2-7
Second method of parameter transfer:
• Values are only transferred (call-by-value)
If the parameters transferred are changed as the subroutine runs this does not have any
effect on the main program. The parameters remain unchanged in it (see Fig.).
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• Parameter transfer with data exchange (call-by-reference)
Any change to the parameters in the subroutine also causes the parameter to change in the
main program (see Fig.).
Example: variable array lengths
%_N_DRILLING_PLATE_MPF Main program
DEF REAL TABLE[100,2] ;Define position table
EXTERN DRILLING_PATTERN (VAR REAL[,2],INT)
TABLE[0,0]=-17.5 ;Define positions
…
TABLE[99.1]=45
DRILLING_PATTERN(TABLE,100) ;Subroutine call
M30
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