-c_local- is not documented, not even "undocumented".
Here's my stab at explaining it.
Normally, local macros are precisely that: local
to the program or do file they are inside.
Thus, the rule is that local macros in
two or more different programs can be
considered totally independent; they don't
know about each other and they
can't interfere with each other. So you could have
program Buda
...
local kardos 1
...
end
program Pest
...
local kardos 2
...
end
and there is no conflict. When -Buda-
is running, one definition applies, and
similarly with -Pest-. Now let's suppose
that in fact -Buda- calls -Pest-
program Buda
...
local kardos 1
....
Pest
...
di `kardos'
end
This makes no difference. When -Buda-
hands over to -Pest-, nothing that -Pest-
does makes any difference to the value
of local macro kardos in -Buda-. The
display will show 1 (assuming, naturally,
that the example shows all code affecting
kardos).
Usually, this is exactly as you want it.
Sometimes, it is nice to be able to
have a way round the rule and to have
a way of passing information back
to a calling program. (There are of course
other ways of doing this, not least globals.)
Consider now
program Buda
...
local kardos 1
....
Pest
...
di `kardos'
end
program Pest
...
c_local kardos = 2
...
end
What the -c_local- does is carry out
a macro definition in the calling program's
space. So the -display- will show 2.
Naturally, the example is silly. But it's
very often useful to hand some task
to a subroutine and get back the answer.
Warning: this is dangerous unless you really understand it.
Nick
[email protected]
dr kardos lászló
> i am not sure what c_local is, and my searches for it have
> failed. can anyone explain?
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