HP SunSoft Pascal 4.0 Manuale Utente Scaricare il pdf (Pagina 97)

Program Construction and Management 73

By default, both deﬁnitions of variable x are public. Thus, when you compile

and link the program and module units, references to x refer to the same

variable, as follows:

If you compile the program giving the -xl option, the variables are private

by default, as follows:

You can get the same effect by explicitly declaring the variable in a private

var section. Similarly, when you use -xl, you can create public variables by

declaring them in a public var section.

As with routine declarations, it is often a good idea to declare public

variables in an include ﬁle. Doing so makes it easier to keep your

declarations consistent.

There are other methods for making variables visible to different units. See

Chapter 5, “Separate Compilation,” for more information.

hostname% pc program_unit3.p module_unit3.p

program_unit.p:

module_unit.p:

Linking:

hostname% a.out

Hello, world for the 1 time.

Hello, world for the 2 time.

Hello, world for the 3 time.

Hello, world for the 4 time.

Hello, world for the 5 time.

hostname% pc -xl program_unit.p module_unit.p

program_unit.p:

module_unit.p:

Linking:

hostname% a.out

Hello, world for the 0 time.

1 2 ... 92 93 94 95 96 97 98 99 100 101 102 ... 332 333

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HP SunSoft Pascal 4.0 Manuale Utente Pagina 97