multiple mains()

[pranav.choudhary]

I hope the question is not silly.
1. Can there me more than one main in a C program.
2. Can main take more arguments thac argc and argv. If yes then whar
are they meant for??

[pemo]

pr**************@gmail.com wrote:

I hope the question is not silly.
1. Can there me more than one main in a C program.
2. Can main take more arguments thac argc and argv. If yes then whar
are they meant for??

1. Nope, main() is a function [albeit the one that's called to start a
program off], and you can only have one function called <whatever> in a C
program - else, how would a call to <whatever> be resolved?

2. I've seen some compilers/environments where a third argument is allowed,
typical called something like char * env[] - it allows one to access
environment variables. However, standard C says that main should either be
int main(void), or int main(int, char **).

--
==============
*Not a pedant*
==============

[Lew Pitcher]

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pr**************@gmail.com wrote:

I hope the question is not silly.
1. Can there me more than one main in a C program.
No. There can be only one main() function in a program.
2. Can main take more arguments thac argc and argv.
No, yes, and maybe.

No. main() is defined to, in a hosted environment, only have two
arguments: int argc, and char **argv . The local declaration of main()
can either be
int main(void)
or
int main(int argc, char **argv)
(or equivalent)

However, some operating environments take some latitude with the
arguments passed to main(). Some Unixish environments, for instance,
include a third argument (char **envp) to provide access to commandline
arguments.
If yes then whar are they meant for??

What ever the implementation/environment dictates. See the relevant
documentation for your C compiler and execution environment for details.


- --

Lew Pitcher, IT Specialist, Corporate Technology Solutions,
Enterprise Technology Solutions, TD Bank Financial Group

(Opinions expressed here are my own, not my employer's)
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[Eric Sosman]

pr**************@gmail.com wrote:

I hope the question is not silly.
1. Can there me more than one main in a C program.
Yes, but at most one can have external linkage and
thus be "the" main() function, the one where program
execution begins.
2. Can main take more arguments thac argc and argv. If yes then whar
are they meant for??

Every hosted C implementation must support the two
forms of "the" main() function required by the Standard:
one form with no arguments and one with two. A given C
implementation may also support other forms if it chooses;
what those other forms are and what they mean is up to
the implementation that chose to support them.

--
Eric Sosman
es*****@acm-dot-org.invalid

[pemo]

Eric Sosman wrote:

pr**************@gmail.com wrote:

I hope the question is not silly.
1. Can there me more than one main in a C program.

Yes, but at most one can have external linkage and
thus be "the" main() function, the one where program
execution begins.

<snip>

True!

So, something like this:

file1.c

void foo(void);

int main(void)
{
foo();

return 0;
}

file2.c

#include <stdio.h>

static void main(void)
{
puts("In second main()");

}

void foo(void)
{
main();
}
--
==============
*Not a pedant*
==============

[pranav.choudhary]

Eric,
Can you plese elaborate, or get me some links where i can learn more
about the first question i had asked.
thanx
pranav

[CBFalconer]

"pr**************@gmail.com" wrote:

Can you plese elaborate, or get me some links where i can learn
more about the first question i had asked.

I see no first question, nor anything to elaborate, here. Perhaps
if you had had the courtesy to include context I would. If the
failure is due to ignorance, rather than rudeness, you can repair
that by reading the following sig and the referenced URLs.

--
"If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson
More details at: <http://cfaj.freeshell.org/google/>
Also see <http://www.safalra.com/special/googlegroupsreply/>

[Keith Thompson]

Lew Pitcher <Le*********@tdsecurities.com> writes:
[...]

However, some operating environments take some latitude with the
arguments passed to main(). Some Unixish environments, for instance,
include a third argument (char **envp) to provide access to commandline
arguments.

No, envp provides access to environment variables.

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Keith Thompson]

"pr**************@gmail.com" <pr**************@gmail.com> writes:

I hope the question is not silly.
1. Can there me more than one main in a C program.

[...]

You can have multiple *static* functions with the same name in a
single program, as long as each is in a separate translation unit.

I don't know whether you can do this with main(). It may be
implementation-dependent. But frankly, I don't particularly care
whether you can have multiple static main() functions. Even if it's
legal, it would be confusing, and the confusion could easily be
avoided by calling the function something other than "main".

Is there some problem that you think would be solved by having
multiple functions called main? If so, there's almost certainly a
better way to solve it. What are you trying to do?

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Lew Pitcher]

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Keith Thompson wrote:

Lew Pitcher <Le*********@tdsecurities.com> writes:
[...]

However, some operating environments take some latitude with the
arguments passed to main(). Some Unixish environments, for instance,
include a third argument (char **envp) to provide access to commandline
arguments.

No, envp provides access to environment variables.

:-(

My bad. Brain f*rt or finger check or something must have caught me. I
/meant/ to say what you said.
- --

Lew Pitcher, IT Specialist, Corporate Technology Solutions,
Enterprise Technology Solutions, TD Bank Financial Group

(Opinions expressed here are my own, not my employer's)
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