function declaration nested?

[Phil Reardon]

Ive been away from programming for a few years and am having difficulty
accessing a function from a math/engineering library that I want to use .
I thought that double foo(double); inserted in the calling routine would
let me say x=foo(y); But I get a warning from the compilation that says
"warning: nested extern declaration of 'foo'. Thanks for any suggestions

[Dan Pop]

In <m3************ @localhost.loca ldomain> Micah Cowan <mi***@cowan.na me> writes:

Da*****@cern.c h (Dan Pop) writes:

In <m3************ @localhost.loca ldomain> Micah Cowan <mi***@cowan.na me> writes:

>"Phil Reardon" <pc**@pcrt.co m> writes:
>
>> Ive been away from programming for a few years and am having difficulty
>> accessing a function from a math/engineering library that I want to use .
>> I thought that double foo(double); inserted in the calling routine would
>> let me say x=foo(y); But I get a warning from the compilation that says
>> "warning: nested extern declaration of 'foo'. Thanks for any suggestions
>
>Please post the minimum compileable (or compile-attemptable) code
>that exhibits the problem you are experiencing; until you do that
>we can only talk about our suspicions, not point out what we know
>to be the problem. "Inserted in the calling routine?"
>
>If you mean you did something like:
>
> void my_name_is_of_n o_consequence(v oid)
> {
> double foo(double);
>
> x=foo(y);
> }
>
>And you got that warning; well, an implementation is within its
>rights to complain about anything it wants to. It may be that the
>implementati on "thinks" that you might have meant to declare
>foo() at file-scope, I dunno. As long as it compiles, there isn't
>really a problem in this case.

I suspect he's including a header that already provides a declaration
for foo().

But then what did he mean by "inserted in the calling routine?"

The very thing you have illustrated above, but there is already a
declaration for foo() in scope, coming from some included header.

Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de