HP SunSoft Pascal 4.0 Using extern, Commands to compile and execute incprog2.p and incmod2.p

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The commands to compile and execute inc_prog2.p and inc_mod2.p

hostname% pc -xl inc_prog2.p inc_mod2.p inc_prog2.p:

inc_mod2.p: Linking: hostname% a.out

From MAIN, before PROC: 1

From PROC: 1

From MAIN, after PROC : 2

The program unit, ext_prog.p

Using extern

In the previous example, the extern definition for variables is put into an include file and then shared. You can do the same for the extern procedure definition. In doing so, you must also declare the variable with a define declaration in the module that defines the procedure. This declaration nullifies the effect of the extern declaration.

program ext_prog;

%include "extern.h";

begin

global := 1;

writeln('From MAIN, before PROC: ',global); proc;

writeln('From MAIN, after PROC: ',global); end. { ext_prog }

86 Pascal 4.0 User’s Guide