[Boost-users] Executable wrapped into another one: how to pass streams instead of real files?

Subject: [Boost-users] Executable wrapped into another one: how to pass streams instead of real files?
From: Alessandro Candini (candini_at_[hidden])
Date: 2011-06-21 08:13:10

I give you a simplified example to explain what I would like to do.
I have the following code, which I cannot modify (hello.cpp):

|#include <iostream>
#include <fstream>
using namespace std;

int main( int argc, char *argv[] )
{
     string line;
     ifstream f( argv[1] );

     while(!f.eof())
     {
         getline(f, line);
         cout << line << endl;
     }

     return 0;
}

Launch example:
||caneta_at_host ~ $ ./hello myfile.txt
1 - This is
2 - a test
3 - file.

I have a wrapper program which I need to modify:
||#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <iostream>
#include <fstream>
#include <sstream>

using namespace std;

int main ()
{
     int ret;

     ret = execl ("./hello", "./hello", "myfile.txt", (char *)0);

     return 0;
}|

In this way it works perfectly...but how can I modify it in order to use 
a stream or a string inside the wrapper program, instead of using a file 
name?
I would like to have something like:

|#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <iostream>
#include <fstream>
#include <sstream>

using namespace std;

int main ()
{
     int ret;
     ifstream inputFile;

     inputFile << "1 - This is" << endl;
     inputFile << "2 - a test" << endl;
     inputFile << "3 - file." << endl;

     ret = execl ("./hello", "./hello", inputFile, (char *)0);

     return 0;
}|

This last example, of course, doesn't work...how can I modify it in 
order to make it work?
Remember that I cannot modify hello.cpp...

Can the Boost.iostreams help me?

Thanks in advance.

-- 
Alessandro Candini
MEEO S.r.l.
Via Saragat 9
I-44122 Ferrara, Italy
Tel: [phone]
Fax: [phone]
http://www.meeo.it
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