NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c++-part2/12966

Text File | 1996-08-05 | 2.8 KB | 107 lines

Path: news.sprintlink.net!datalytics!usenet
From: Rob Stewart <[e-mail]>
Newsgroups: comp.lang.c++
Subject: Re: Simple Question for the GURUs....
Date: Fri, 22 Mar 1996 13:53:57 -0500
Organization: Datalytics, Inc
Message-ID: <[e-mail]>
References: <[e-mail]>
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[e-mail] wrote:
>
> *** A stupid question for the GURUS ***
>
> I have a very simple problem. Should the following code work ?
>

No.  The correct signature for main is:

int main(int argc, char **argv, char **env);

or, if you prefer:

int main(int argc, char *argv[], char *env[]);

You can also omit the parameters you don't want (from the
right), so these are also permissible:

int main(int argc, char **argv);
int main(int argc);
int main(void);

In each case, however, note that the return type is int.  You
cannot return a string, though some compilers will allow you to
declare main as returning void (they will return zero for you).

> //File:myapp.c
>
>         char *main(int argc, char *argv[])
>         {
>            char *temp = (char *)NULL;

This was a useless assignment, and the cast is not necessary.

>
>            temp = (char *)malloc(40 * sizeof(char) );

Try this instead of using malloc:

char *temp = new char[40];

>
>            if ( temp ) strcpy(temp,"Hello World..!!");
>
>            return(temp);
>         }
>
> My intent is to have my myapp.exe return to me a string as it should do.

The only way to "return" a string is to write it to some IPC,
like a pipe or socket, or print it to stdout.  The typical way
to do what you want is to write to stdout:

#include <iostream.h>    // cout

int main(void)
{
    cout << "Hello World!" << endl;
    return 0;
}

>
> The next part of my problem is I am setting a variable say ALPHA to the string
> coming out of this executable. I am doing this in a PERL script as follows:
>
> //File: myperl.cmd
> ..............
> ............
>         @GREETINGS = `myapp.exe`;
>         print "Greetings from the Master : @GREETINGS\n";
> ...........
> ..........
>
> I am doing this in Windows NT environment.The PERL script appear to hang at the
> line @GREETINGS = `myapp.exe`. What is the problem.
>

With the change I gave above, your code should work fine.  The
Perl code you wrote is waiting to capture the stdout output from
myapp.exe.  Since there is none, there is nothing to capture.

> I will appreciate a response from anyone, who can help solve this apparently
> simple problem. Please e-mail me directly at "[e-mail]".
>
> Hoping to hear from someone there.
>
> thanks
> akhtar

--
Robert Stewart        | My opinions are usually my own.
Datalytics, Inc.    | [e-mail]