How to call another separate program and passing some variables in C?

How to call another separate program and passing some variables in C?

[johnny_xing]

Hi,

Forgive me if my question is so simple as I am a newbie to programming..

I have two C programming and I want to call second C file within my first C
program, upon calling, I need to pass some variables (like 1 or 0) to the
second program.

Can anyone tell me how to do? I searched system() but it seems not be able
to do this.

Thanks & Best Regards,
 
Johnny


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Re : How to call another separate program and passing some variables in C?

[korfuri]

2008/10/14, johnny_xing <johnny_xing@banshing.com>:
> Hi,
>
> Forgive me if my question is so simple as I am a newbie to programming..
>
> I have two C programming and I want to call second C file within my first C
> program, upon calling, I need to pass some variables (like 1 or 0) to the
> second program.
>
> Can anyone tell me how to do? I searched system() but it seems not be able
> to do this.
>
> Thanks & Best Regards,
>
> Johnny
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe
> linux-c-programming" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Hi,

You can use system() if you build the command-line (e.g. with
sprintf()) to pass the arguments you want. Then you can access it in
your 2nd program with argc/argv.

An alternative is to use fork() and execve(). Please note that you
have to convert each argument to a string so execve() can use it. Here
again you can use sprintf() for this purpose.

But are you sure you need two separate programs ? You can build 2 C
files together into one binary. That makes passing variables much
easier as it results to a normal function call.

Hope this will help
Regards,
Uriel

-- 
Uriel "Korfuri" Corfa
Epitech student

RE: How to call another separate program and passing some variables in C?

[johnny_xing]

Hi, Uriel

Yes I need to execute two separate programs although I know it would be much
easier if I could put into one program.

The reason is the first program invokes lots of other modules and program
and it has been fixed and running that I don't know how to add in the second
program.

However, if I could invoke the second program using system() and pass some
integers to the second program to generate the output I want, it will be
good enough.

Eg: system("/usr/local/src/program2"); 

The problem is I don't know how to pass some integers upon invoking it.

Is it something like this if I want to pass an integer 1?
system("/usr/local/src/program2" 1);

Thanks & Best Regards,
 
Johnny Xing
-----Original Message-----
From: linux-c-programming-owner@vger.kernel.org
[mailto:linux-c-programming-owner@vger.kernel.org] On Behalf Of
korfuri@gmail.com
Sent: 2008年10月14日 19:12
To: johnny_xing
Cc: linux-c-programming@vger.kernel.org
Subject: Re : How to call another separate program and passing some
variables in C?

2008/10/14, johnny_xing <johnny_xing@banshing.com>:
> Hi,
>
> Forgive me if my question is so simple as I am a newbie to programming..
>
> I have two C programming and I want to call second C file within my first
C
> program, upon calling, I need to pass some variables (like 1 or 0) to the
> second program.
>
> Can anyone tell me how to do? I searched system() but it seems not be able
> to do this.
>
> Thanks & Best Regards,
>
> Johnny
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe
> linux-c-programming" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Hi,

You can use system() if you build the command-line (e.g. with
sprintf()) to pass the arguments you want. Then you can access it in
your 2nd program with argc/argv.

An alternative is to use fork() and execve(). Please note that you
have to convert each argument to a string so execve() can use it. Here
again you can use sprintf() for this purpose.

But are you sure you need two separate programs ? You can build 2 C
files together into one binary. That makes passing variables much
easier as it results to a normal function call.

Hope this will help
Regards,
Uriel

-- 
Uriel "Korfuri" Corfa
Epitech student
--
To unsubscribe from this list: send the line "unsubscribe
linux-c-programming" in
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RE: How to call another separate program and passing some variables in C?

[johnny_xing]

Hi,

I tried as what Hlalesh said and it doesn’t work.

Here is what I have:

In program 1:

system(“/usr/local/src/program2 1”);

In program 2:
int main(int argc, char *argv[])
{
int input1;
char buffer[10];
sprintf(buffer, argv[0]);

printf("buffer is %s\n", buffer);
input1 =atoi(buffer);
printf("input1 value is %d\n",input1);
}

The output is:

buffer is /usr/local/src/parallel/asterisk
input1 value is 0


Anything wrong with it?


Thanks & Best Regards,
 
Johnny Xing
 
________________________________________
From: Halesh S [mailto:halesh.tux@gmail.com] 
Sent: 2008年10月15日 14:34
To: johnny_xing
Cc: korfuri@gmail.com; linux-c-programming@vger.kernel.org
Subject: Re: How to call another separate program and passing some variables in C?


2008/10/15 johnny_xing <johnny_xing@banshing.com>
Hi, Uriel

Yes I need to execute two separate programs although I know it would be much
easier if I could put into one program.

The reason is the first program invokes lots of other modules and program
and it has been fixed and running that I don't know how to add in the second
program.

However, if I could invoke the second program using system() and pass some
integers to the second program to generate the output I want, it will be
good enough.

Eg: system("/usr/local/src/program2");

The problem is I don't know how to pass some integers upon invoking it.

Is it something like this if I want to pass an integer 1?
system("/usr/local/src/program2" 1);

  Use system("/usr/local/src/program2 1");

  the argument will stored as string in *argv[] in 2nd prog.
  Convert back to integer using sprintf / any of ur own method.

 Halesh
  


Thanks & Best Regards,

Johnny Xing
-----Original Message-----
From: linux-c-programming-owner@vger.kernel.org
[mailto:linux-c-programming-owner@vger.kernel.org] On Behalf Of
korfuri@gmail.com
Sent: 2008年10月14日 19:12
To: johnny_xing
Cc: linux-c-programming@vger.kernel.org
Subject: Re : How to call another separate program and passing some
variables in C?

2008/10/14, johnny_xing <johnny_xing@banshing.com>:
> Hi,
>
> Forgive me if my question is so simple as I am a newbie to programming..
>
> I have two C programming and I want to call second C file within my first
C
> program, upon calling, I need to pass some variables (like 1 or 0) to the
> second program.
>
> Can anyone tell me how to do? I searched system() but it seems not be able
> to do this.
>
> Thanks & Best Regards,
>
> Johnny
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe
> linux-c-programming" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Hi,

You can use system() if you build the command-line (e.g. with
sprintf()) to pass the arguments you want. Then you can access it in
your 2nd program with argc/argv.

An alternative is to use fork() and execve(). Please note that you
have to convert each argument to a string so execve() can use it. Here
again you can use sprintf() for this purpose.

But are you sure you need two separate programs ? You can build 2 C
files together into one binary. That makes passing variables much
easier as it results to a normal function call.

Hope this will help
Regards,
Uriel

--
Uriel "Korfuri" Corfa
Epitech student
--
To unsubscribe from this list: send the line "unsubscribe
linux-c-programming" in
the body of a message to majordomo@vger.kernel.org
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Re: How to call another separate program and passing some variables in C?

[Per Jessen]

johnny_xing wrote:
> Hi,
> 
> I tried as what Hlalesh said and it doesn’t work.
> 
> Here is what I have:
> 
> In program 1:
> 
> system(“/usr/local/src/program2 1”);
> 
> In program 2:
> int main(int argc, char *argv[])
> {
> int input1;
> char buffer[10];
> sprintf(buffer, argv[0]);
> 
> printf("buffer is %s\n", buffer);
> input1 =atoi(buffer);
> printf("input1 value is %d\n",input1);
> }
> 
> The output is:
> 
> buffer is /usr/local/src/parallel/asterisk
> input1 value is 0
> 

argv[0] is always the name of the called binary.  To get the arguments, 
you need to start with argv[1].

Surely you can see that atoi("/usr/local/src/parallel/asterisk") is 0 as 
there is no way to convert "/usr/local/src/parallel/asterisk" to an integer.


/Per Jessen, Zurich
	

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RE: How to call another separate program and passing some variables in C?

[johnny_xing]

Hi, Halesh,

Same result as above, I am wondering if system() should be used if we want to pass some arguments as well.

Thanks & Best Regards,
 
Johnny Xing
 
________________________________________
From: Halesh S [mailto:halesh.tux@gmail.com] 
Sent: 2008年10月15日 16:52
To: johnny_xing
Cc: korfuri@gmail.com; linux-c-programming@vger.kernel.org
Subject: Re: How to call another separate program and passing some variables in C?

Try program 2 as below, no need to use sprintf

In program 2:
int main(int argc, char *argv[])
{
int input1;
printf("buffer is %s\n", argv[0]);
input1 =atoi(argv[0]);
printf("input1 value is %d\n",input1);
}
Halesh



Try program 2 as below, no need to use sprintf

In program 2:
int main(int argc, char *argv[])
{
int input1;
char buffer[10];
printf("buffer is %s\n", buffer);
input1 =atoi(buffer);
printf("input1 value is %d\n",input1);
}
 - Halesh 

2008/10/15 johnny_xing <johnny_xing@banshing.com>
2008/10/15 johnny_xing <johnny_xing@banshing.com>
Hi,
 
I tried as what Hlalesh said and it doesn't work.
 
Here is what I have:
 
In program 1:
 
system("/usr/local/src/program2 1");
 
In program 2:
int main(int argc, char *argv[])
{
int input1;
char buffer[10];
sprintf(buffer, argv[0]);
 
printf("buffer is %s\n", buffer);
input1 =atoi(buffer);
printf("input1 value is %d\n",input1);
}
 
The output is:
 
buffer is /usr/local/src/parallel/asterisk
input1 value is 0
 
 
Anything wrong with it?
 
 
Thanks & Best Regards,
 
Johnny Xing
 
________________________________________
From: Halesh S [mailto:halesh.tux@gmail.com] 
Sent: 2008年10月15日 14:34
To: johnny_xing
Cc: korfuri@gmail.com; linux-c-programming@vger.kernel.org

Subject: Re: How to call another separate program and passing some variables in C?
 
 
2008/10/15 johnny_xing <johnny_xing@banshing.com>
Hi, Uriel

Yes I need to execute two separate programs although I know it would be much
easier if I could put into one program.

The reason is the first program invokes lots of other modules and program
and it has been fixed and running that I don't know how to add in the second
program.

However, if I could invoke the second program using system() and pass some
integers to the second program to generate the output I want, it will be
good enough.

Eg: system("/usr/local/src/program2");

The problem is I don't know how to pass some integers upon invoking it.

Is it something like this if I want to pass an integer 1?
system("/usr/local/src/program2" 1);

  Use system("/usr/local/src/program2 1");

  the argument will stored as string in *argv[] in 2nd prog.
  Convert back to integer using sprintf / any of ur own method.

 Halesh
  


Thanks & Best Regards,

Johnny Xing
-----Original Message-----
From: linux-c-programming-owner@vger.kernel.org
[mailto:linux-c-programming-owner@vger.kernel.org] On Behalf Of
korfuri@gmail.com
Sent: 2008年10月14日 19:12
To: johnny_xing
Cc: linux-c-programming@vger.kernel.org
Subject: Re : How to call another separate program and passing some
variables in C?

2008/10/14, johnny_xing <johnny_xing@banshing.com>:
> Hi,
>
> Forgive me if my question is so simple as I am a newbie to programming..
>
> I have two C programming and I want to call second C file within my first
C
> program, upon calling, I need to pass some variables (like 1 or 0) to the
> second program.
>
> Can anyone tell me how to do? I searched system() but it seems not be able
> to do this.
>
> Thanks & Best Regards,
>
> Johnny
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe
> linux-c-programming" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Hi,

You can use system() if you build the command-line (e.g. with
sprintf()) to pass the arguments you want. Then you can access it in
your 2nd program with argc/argv.

An alternative is to use fork() and execve(). Please note that you
have to convert each argument to a string so execve() can use it. Here
again you can use sprintf() for this purpose.

But are you sure you need two separate programs ? You can build 2 C
files together into one binary. That makes passing variables much
easier as it results to a normal function call.

Hope this will help
Regards,
Uriel

--
Uriel "Korfuri" Corfa
Epitech student
--
To unsubscribe from this list: send the line "unsubscribe
linux-c-programming" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

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RE: How to call another separate program and passing some variables in C?

[johnny_xing]

Yes that works for me as well.

Thanks a lot guys.

Thanks & Best Regards,
 
Johnny Xing
________________________________________
From: Halesh S [mailto:halesh.tux@gmail.com] 
Sent: 2008年10月15日 17:28
To: johnny_xing
Cc: korfuri@gmail.com; linux-c-programming@vger.kernel.org
Subject: Re: How to call another separate program and passing some variables in C?

Please check below
argv[0] will have prgram name itself...so its giving 0...
Start from argv[1] :)


Try below, I am able to valid result.

prog1.c
------------
int main()
{
  system("./prog2 1 2 3");
  exit(0);
}

prog2.c
-------------

int main(int argc, char *argv[])
{
  int input1,i;
  for (i=1; i<argc; i++) {
- Hide quoted text -

    printf("buffer is %s\n", argv[i]);
    input1 =atoi(argv[i]);

   printf("input1 value is %d\n",input1);
 }
}
run prog1, i am able to get proper result.

Thanks,
Halesh
On Wed, Oct 15, 2008 at 2:40 PM, johnny_xing <johnny_xing@banshing.com> wrote:
Hi, Halesh,

Same result as above, I am wondering if system() should be used if we want to pass some arguments as well.

Thanks & Best Regards,

Johnny Xing

________________________________________
From: Halesh S [mailto:halesh.tux@gmail.com]
Sent: 2008年10月15日 16:52
To: johnny_xing
Cc: korfuri@gmail.com; linux-c-programming@vger.kernel.org
Subject: Re: How to call another separate program and passing some variables in C?

Try program 2 as below, no need to use sprintf

In program 2:
int main(int argc, char *argv[])
{
int input1;
printf("buffer is %s\n", argv[0]);
input1 =atoi(argv[0]);
printf("input1 value is %d\n",input1);
}
Halesh



Try program 2 as below, no need to use sprintf

In program 2:
int main(int argc, char *argv[])
{
int input1;
char buffer[10];
printf("buffer is %s\n", buffer);
input1 =atoi(buffer);
printf("input1 value is %d\n",input1);
}
 - Halesh

2008/10/15 johnny_xing <johnny_xing@banshing.com>
2008/10/15 johnny_xing <johnny_xing@banshing.com>
Hi,

I tried as what Hlalesh said and it doesn't work.

Here is what I have:

In program 1:

system("/usr/local/src/program2 1");

In program 2:
int main(int argc, char *argv[])
{
int input1;
char buffer[10];
sprintf(buffer, argv[0]);

printf("buffer is %s\n", buffer);
input1 =atoi(buffer);
printf("input1 value is %d\n",input1);
}

The output is:

buffer is /usr/local/src/parallel/asterisk
input1 value is 0


Anything wrong with it?


Thanks & Best Regards,

Johnny Xing

________________________________________
From: Halesh S [mailto:halesh.tux@gmail.com]
Sent: 2008年10月15日 14:34
To: johnny_xing
Cc: korfuri@gmail.com; linux-c-programming@vger.kernel.org

Subject: Re: How to call another separate program and passing some variables in C?


2008/10/15 johnny_xing <johnny_xing@banshing.com>
Hi, Uriel

Yes I need to execute two separate programs although I know it would be much
easier if I could put into one program.

The reason is the first program invokes lots of other modules and program
and it has been fixed and running that I don't know how to add in the second
program.

However, if I could invoke the second program using system() and pass some
integers to the second program to generate the output I want, it will be
good enough.

Eg: system("/usr/local/src/program2");

The problem is I don't know how to pass some integers upon invoking it.

Is it something like this if I want to pass an integer 1?
system("/usr/local/src/program2" 1);

 Use system("/usr/local/src/program2 1");

 the argument will stored as string in *argv[] in 2nd prog.
 Convert back to integer using sprintf / any of ur own method.

 Halesh



Thanks & Best Regards,

Johnny Xing
-----Original Message-----
From: linux-c-programming-owner@vger.kernel.org
[mailto:linux-c-programming-owner@vger.kernel.org] On Behalf Of
korfuri@gmail.com
Sent: 2008年10月14日 19:12
To: johnny_xing
Cc: linux-c-programming@vger.kernel.org
Subject: Re : How to call another separate program and passing some
variables in C?

2008/10/14, johnny_xing <johnny_xing@banshing.com>:
> Hi,
>
> Forgive me if my question is so simple as I am a newbie to programming..
>
> I have two C programming and I want to call second C file within my first
C
> program, upon calling, I need to pass some variables (like 1 or 0) to the
> second program.
>
> Can anyone tell me how to do? I searched system() but it seems not be able
> to do this.
>
> Thanks & Best Regards,
>
> Johnny
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe
> linux-c-programming" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Hi,

You can use system() if you build the command-line (e.g. with
sprintf()) to pass the arguments you want. Then you can access it in
your 2nd program with argc/argv.

An alternative is to use fork() and execve(). Please note that you
have to convert each argument to a string so execve() can use it. Here
again you can use sprintf() for this purpose.

But are you sure you need two separate programs ? You can build 2 C
files together into one binary. That makes passing variables much
easier as it results to a normal function call.

Hope this will help
Regards,
Uriel

--
Uriel "Korfuri" Corfa
Epitech student
--
To unsubscribe from this list: send the line "unsubscribe
linux-c-programming" in
the body of a message to majordomo@vger.kernel.org
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Re: How to call another separate program and passing some variables in C?

[Jianjun Kong]

On Wed, Oct 15, 2008 at 05:10:36PM +0800, johnny_xing wrote:
>Hi, Halesh,
>
>Same result as above, I am wondering if system() should be used if we want to pass some arguments as well.

$ man system

You can get more information :)



>Thanks & Best Regards,
> 
>Johnny Xing