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hi,
I've a very large C program consisting of hundred of files; I want to
know what are all
the global variables defined in the program. how do i do this.

thanks

sinbad <> writes:

> hi,
> I've a very large C program consisting of hundred of files; I want to
> know what are all
> the global variables defined in the program. how do i do this.

One way would be to compile them and then extract this information from
the object files. On a Unix system, this would probably be easiest to
do by parsing the output of nm(1). On my FreeBSD system, I'd do

nm *.o |grep '[0-9A-Fa-f]* [BCDGRS]' |cut -d ' ' -f 3

Testing this, it appears that it will miss global constants, i.e., a
`const' variable with external linkage, because they get stored in the
..text section. Changing the above regexp to '[0-9A-Fa-f]* [BCDGRST]'
would include them, but would also include all functions with external
linkage, which might not be what you want. However, it's a start, I
guess.

Nate Eldredge <> writes:
> sinbad <> writes:
>
>> hi,
>> I've a very large C program consisting of hundred of files; I want to
>> know what are all
>> the global variables defined in the program. how do i do this.
>
> One way would be to compile them and then extract this information from
> the object files. On a Unix system, this would probably be easiest to
> do by parsing the output of nm(1). On my FreeBSD system, I'd do
>
> nm *.o |grep '[0-9A-Fa-f]* [BCDGRS]' |cut -d ' ' -f 3
>
> Testing this, it appears that it will miss global constants, i.e., a
> `const' variable with external linkage, because they get stored in the
> .text section. Changing the above regexp to '[0-9A-Fa-f]* [BCDGRST]'
> would include them, but would also include all functions with external
> linkage, which might not be what you want. However, it's a start, I
> guess.

It also misses the global variables which have not been
included in the particular build configuration. If you're
auditing source code, then this:

#if defined(__MIPS__) && defined(__GCC__) && defined(PROFILING) && (PROFILING>2)
int tally;
#endif

definitely still has a global variable, even if you've never built
for MIPS for years. The solution, however, depends a lot on how
sane and strictly adhered to your coding standards are. Again,
I know that a grep would solve the problem on my own source code
trees, as my global variables are always declared in the same way,
and in a way that functions, function-local variables, function
parameters, struct members, ... aren't,

Phil
--
I tried the Vista speech recognition by running the tutorial. I was
amazed, it was awesome, recognised every word I said. Then I said the
wrong word ... and it typed the right one. It was actually just
detecting a sound and printing the expected word! -- pbhj on /.

On Nov 9, 5:37*pm, Phil Carmody <thefatphil_demun...@yahoo.co.uk>
wrote:
> Nate Eldredge <n...@vulcan.lan> writes:
> >sinbad <sinbad.sin...@gmail.com> writes:
>
> >> hi,
> >> I've a very large C program consisting of hundred of files; I want to
> >> know what are all
> >> the global variables defined in the program. how do i do this.
>
> > One way would be to compile them and then extract this information from
> > the object files. *On a Unix system, this would probably be easiest to
> > do by parsing the output of nm(1). *On my FreeBSD system, I'd do
>
> > nm *.o |grep '[0-9A-Fa-f]* [BCDGRS]' |cut -d ' ' -f 3
>
> > Testing this, it appears that it will miss global constants, i.e., a
> > `const' variable with external linkage, because they get stored in the
> > .text section. *Changing the above regexp to '[0-9A-Fa-f]* [BCDGRST]'
> > would include them, but would also include all functions with external
> > linkage, which might not be what you want. *However, it's a start, I
> > guess.
>
> It also misses the global variables which have not been
> included in the particular build configuration. If you're
> auditing source code, then this:
>
> #if defined(__MIPS__) && defined(__GCC__) && defined(PROFILING) && (PROFILING>2)
> int tally;
> #endif
>
> definitely still has a global variable, even if you've never built
> for MIPS for years. The solution, however, depends a lot on how
> sane and strictly adhered to your coding standards are. Again,
> I know that a grep would solve the problem on my own source code
> trees, as my global variables are always declared in the same way,
> and in a way that functions, function-local variables, function
> parameters, struct members, ... aren't,
>
> Phil
> --
> I tried the Vista speech recognition by running the tutorial. I was
> amazed, it was awesome, recognised every word I said. Then I said the
> wrong word ... and it typed the right one. It was actually just
> detecting a sound and printing the expected word! -- pbhj on /.

Hi,
Is there any way to do it by parsing the code statically. More
specifically i want to do this by writing a script for example
in perl.

thanks

sinbad <> writes:

> On Nov 9, 5:37Â*pm, Phil Carmody <thefatphil_demun...@yahoo.co.uk>
> wrote:
>> Nate Eldredge <n...@vulcan.lan> writes:
>> >sinbad <sinbad.sin...@gmail.com> writes:
>>
>> >> I've a very large C program consisting of hundred of files; I want to
>> >> know what are all
>> >> the global variables defined in the program. how do i do this.
<snip>
>> Phil
>> --
>> I tried the Vista speech...

It is not a good idea to quote a sig (unless you are commenting on
it).

> Is there any way to do it by parsing the code statically.

Of course! C implementations do this all the time -- the trouble is
it is hard.

> More
> specifically i want to do this by writing a script for example
> in perl.

Feels like a hard problem to me. For starters, borrow a C
pre-processor so you don't have to do that part.

If your sources are clear and well-structured and you feel you can
take some shortcuts, then the problem might not be too complex.

The odd thing in all this is that a C implementation is obliged to
tell you if you have references to undefined objects. Can't you just
compile and filter the output?

--
Ben.

Ben Bacarisse wrote:
> sinbad <> writes:
>
>> On Nov 9, 5:37 pm, Phil Carmody <thefatphil_demun...@yahoo.co.uk>
>> wrote:
>>> Nate Eldredge <n...@vulcan.lan> writes:
>>>> sinbad <sinbad.sin...@gmail.com> writes:
>>>>> I've a very large C program consisting of hundred of files; I want to
>>>>> know what are all
>>>>> the global variables defined in the program. how do i do this.
....
> The odd thing in all this is that a C implementation is obliged to
> tell you if you have references to undefined objects. Can't you just
> compile and filter the output?

That would tell him which objects aren't defined, but are referenced. It
sounds to me like he wants a list of objects which are defined, whether
or not they've been referenced.

James Kuyper <> writes:

> Ben Bacarisse wrote:
>> sinbad <> writes:
>>
>>> On Nov 9, 5:37 pm, Phil Carmody <thefatphil_demun...@yahoo.co.uk>
>>> wrote:
>>>> Nate Eldredge <n...@vulcan.lan> writes:
>>>>> sinbad <sinbad.sin...@gmail.com> writes:
>>>>>> I've a very large C program consisting of hundred of files; I want to
>>>>>> know what are all
>>>>>> the global variables defined in the program. how do i do this.
> ...
>> The odd thing in all this is that a C implementation is obliged to
>> tell you if you have references to undefined objects. Can't you just
>> compile and filter the output?
>
> That would tell him which objects aren't defined, but are
> referenced. It sounds to me like he wants a list of objects which are
> defined, whether or not they've been referenced.

Ah, OK. Then ctags + the compiler's output!

--
Ben.

On 11 Nov, 13:02, Ben Bacarisse <ben.use...@bsb.me.uk> wrote:
> sinbad <sinbad.sin...@gmail.com> writes:
> > On Nov 9, 5:37*pm, Phil Carmody <thefatphil_demun...@yahoo.co.uk>
> > wrote:
> >> Nate Eldredge <n...@vulcan.lan> writes:
> >> >sinbad <sinbad.sin...@gmail.com> writes:
>
> >> >> I've a very large C program consisting of hundred of files; I want to
> >> >> know what are all
> >> >> the global variables defined in the program. how do i do this.
> <snip>
> >> Phil
> >> --
> >> I tried the Vista speech...
>
> It is not a good idea to quote a sig (unless you are commenting on
> it).
>
> > Is there any way to do it by parsing the code statically.
>
> Of course! *C implementations do this all the time -- the trouble is
> it is hard.
>
> > More
> > specifically i want to do this by writing a script for example
> > in perl.
>
> Feels like a hard problem to me. *For starters, borrow a C
> pre-processor so you don't have to do that part.
>
> If your sources are clear and well-structured and you feel you can
> take some shortcuts, then the problem might not be too complex.
>
> The odd thing in all this is that a C implementation is obliged to
> tell you if you have references to undefined objects.

I have encountered ones that don't (ok, technically that isn't
a C implementation). Missing dynamically linked functions
were not dectected until run time.

>*Can't you just
> compile and filter the output?


--
Nick Keighley

Nick Keighley wrote:
) On 11 Nov, 13:02, Ben Bacarisse <ben.use...@bsb.me.uk> wrote:
)> The odd thing in all this is that a C implementation is obliged to
)> tell you if you have references to undefined objects.
)
) I have encountered ones that don't (ok, technically that isn't
) a C implementation). Missing dynamically linked functions
) were not dectected until run time.

Technically, it *is* a C implementation, it's just that (part of)
the last compilation step is deferred to run time.

^_^


SaSW, Willem
--
Disclaimer: I am in no way responsible for any of the statements
made in the above text. For all I know I might be
drugged or something..
No I'm not paranoid. You all think I'm paranoid, don't you !
#EOT

On 12 Nov, 10:49, Willem <wil...@stack.nl> wrote:
> Nick Keighley wrote:
>
> ) On 11 Nov, 13:02, Ben Bacarisse <ben.use...@bsb.me.uk> wrote:
> )> The odd thing in all this is that a C implementation is obliged to
> )> tell you if you have references to undefined objects.
> )
> ) I have encountered ones that don't (ok, technically that isn't
> ) a C implementation). Missing dynamically linked functions
> ) were not dectected until run time.
>
> Technically, it *is* a C implementation, it's just that (part of)
> the last compilation step is deferred to run time.

is that actually standard compliant? Translation Phase 8
says

[paraphrase] all references are resolved, all translator output is
collected into a program imagewhich conatins information needed for
execution. [end]

yes if TP8 is deferred until just before the program starts
to run the that's ok. But I think I've seen cases where it wasn't
until the function was actually called that things went wrong.

--
Nick Keighley