SUBROUTINE: initial statement of a subroutine subprogram

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⇒ Example of a SUBROUTINE call in "Mouse_position" (RosettaCode)

A subroutine subprogram is invoked in
- a CALL statement
- in the ALARM() function
- in a callback from many HicEst functions.
Unlike the FUNCTION procedure a subroutine does not return a particular value. It may return variable values only via the parameter list.
The following are examples of subroutines and how to call them. The procedures differ in the scope of variables, either local or global
⇒ Programming (procedures)
this by the way is a complete HicEst script

REAL :: var1=111.111, var2=222.222
CHARACTER MENU="hello world; good morning", selected_text*20
    CALL SUB_no_USE_no_ARG
    CALL SUB_with_USE
    CALL SUB_with_ARG( var1, var2^2, "hello world") ! parameter list with 3 actual arguments
    CALL SUB_with_ARG_and_USE( var1+var2 )
    ALARM(2.3, 5) ! calls F5 in 2.3 sec
    POP(Menu=MENU, SelTxt=selected_text) ! calls MENU from popup menu
 END

SUBROUTINE SUB_no_USE_no_ARG
    ! definitions are global
    WRITE(Messagebox, Name) var1, var2, var3
END       ! message box output: var1=111.111; var2=222.222; var3=0;

SUBROUTINE SUB_with_USE
 USE : var2        ! use a global variable
    ! with USE definitions are local
    var3 = 333.333 ! this is a local variable
    WRITE(Messagebox, Name) var1, var2, var3
 END       ! message box output: var1=0; var2=222.222; var3=333.333;

SUBROUTINE SUB_with_ARG(dummy1, dummy2, dummy3) ! 3 dummy arguments
 CHARACTER dummy3 ! string dummies must be defined
    ! with arguments definitions are local
    WRITE(Messagebox, Name) dummy1, dummy2, dummy3
 END       ! message box output: var1=111.111; dummy2=49382.61728; dummy3=hello world;

SUBROUTINE SUB_with_ARG_and_USE(dummy1)
 USE : var2
 USE SUB_with_USE : var3
    WRITE(Messagebox, Name) dummy1, var2, var3
 END       ! message box output: dummy1=333.333; var2=222.222; var3=333.333;

SUBROUTINE F5 ! alarm subroutine, also on toolbar
    time = TIME()/60/60/24 ! fractional day
    WRITE(Messagebox, Format="UHH:mm:SS") time
 END       ! message box output: 16:58:34

SUBROUTINE MENU ! example of a callback routine
    WRITE(Messagebox, Name) $$, selected_text
 END       ! message box output: $$=2; selected_text=good morning;