dev-cpp-users

RE: [Dev-C++] execution of a string with system()

[Santiago P. C. <San...@yd...>]

Hi *,

Simon, you can both use a char array (buffer) from the beginning or use
string and then copy the contents to a char array (buffer), anyway this i=
s a
mixed C/C++ situation:

1st)=20
#include <iostream>=20
#include <stdlib.h>

#define BUFFER_SIZE	32

int main()
{=20
char 	 szIP[BUFFER_SIZE];
char 	 szCommand[BUFFER_SIZE];

cout << "Enter the ip to trace:";
cin >> szIP; //enter domain-name of pc

sprintf(szCommand,"tracert %s",szIP);

system(szCommand);
system("PAUSE");
return 0;=20
}=20


Or the 2nd option)

#include <iostream>=20
#include <string>
#include <stdlib.h>

#define BUFFER_SIZE	32

char*	ConvertStringToSzData(string strValue)=20
{
=09int  iStrLen =3D strValue.size();
=09char* pSzData =3D (char*) malloc( (iStrLen+1)*sizeof(char) );

=09if (pSzData)
=09{
=09	strncpy(pSzData,strValue.data(),iStrLen);
=09	// NULL TERMINATED STRING ;o)
=09	pSzData[iStrLen] =3D '\0';
=09}

=09return pSzData;
}

int main()
{=20
string strIP;
char 	 szCommand[BUFFER_SIZE];

char* pSzIP =3D NULL;

cout << "Enter the ip to trace:";
cin >> strIP; //enter domain-name of pc

pSzIP =3D ConvertStringToSzData(strIP);

if (pSzIP)
{
=09sprintf(szCommand,"tracert %s",pSzIP);

=09free(pSzIP);

=09system(szCommand);
}
else
=09cout << "ERROR: Cannot convert string to char array!" << endl;

system("PAUSE");
return 0;=20
}=20

Hope this helps!
Santy

-----Original Message-----
From: Simon Johner [mailto:el...@op...]=20
Sent: mi=E9rcoles, 18 de septiembre de 2002 16:29
To: dev...@li...
Subject: [Dev-C++] execution of a string with system()


Hello everybody,

I tried to write a programm which does execute some dos command (like
tracert, ping etc.) with an ip.

At first, I created a string (#include <string>), but when I tried to
execute it with the system()-command, I got the following error
(exec=3Dstring-Variable): "cannot convert 'exec' from type string to type=

'const char*'"

Finally -after some hours of trying :)- I've got the following solution:

#include <iostream>=20
#include <stdlib.h>


int main()
{=20
int i;
char pcno[20];

cout << "Enter the ip to trace:" , cin >> pcno; //enter domain-name of pc=

(domain-name is supposed to be 8 chars long)

for (i=3D0;i<8;i++){pcno[i+8]=3Dpcno[i];}; //put the domain name at the e=
nd
pcno[0]=3D't'; pcno[1]=3D'r'; pcno[2]=3D'a';
pcno[3]=3D'c';                           //enter the dos-command in the f=
irst
chars
pcno[4]=3D'e';
pcno[5]=3D'r';
pcno[6]=3D't';
pcno[7]=3D' ';
for (i=3D16;i<40;i++){pcno[i]=3D' ';};

system(pcno);
system("PAUSE");
return 0;=20
}=20


Does someone know an easier solution?

Tanks for your help.

Simon
--=20
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RE: [Dev-C++] execution of a string with system()

[Stringer, A. <Adr...@as...>]

---
#include "stdio.h"
#include "string.h"
#include "stdlib.h"
---
I may be wrong here, and if so feel free to slap me, but I think that ought
to be

#include <cstdio>
#include <cstring>
#include <cstdlib>

and your own header files should be included as

#include "myheader.h"

See the end of http://www.comeaucomputing.com/techtalk/#cname.  I quote:
-->
Similarly, the Standard C headers, such as <stdio.h>, are supported in C++,
but they are deprecated. Instead, so-called Cname headers are preferred, for
instance, cstdio, or cctype instead of ctype.h Furthermore, names in the .h
are assumed to be in the global namespace, and so therefore do not need to
be qualified with std::. The .h form is sometimes used as a transition model
for backwards compatibility. Or, for a "co-ed" source file able to be
compiled by a C or C++ compiler. 
<--

Sorry to be pedantic,

	Adrian

[Dev-C++] Re: execution of a string with system()

[Christophe C. <chr...@fr...>]

Hello,

think Abhijit Shylanath mistyped his response - should be (untested too) :

string whatever = "foo";
system(whatever.c_str());

This will execute the command "foo" on your system.

Little tip : system() returns an integer value, but on many systems, this
is not the plain return code of the executed command. If you need to test
the command's return code, use (will work on many - but maybe not all -
systems)  :

int returncode=system(whatever.c_str()) >> 8;

This is because on these systems, the return code of the command is stored
in the 8 upper bits of a 16 bits integer. The ">> 8" says "take all the
bits of this integer and shift them 8 times on right". Thus, the 8 upper
bits takes place of the 8 lower ones, and the value of the whole integer
becames now the command's return code.
Example :
      0011001100011100 >> 8 = 0000000000110011

Before ending, a little warning : if you want to execute system commands in
a multi-threaded program, you MUSN'T use the system() function. You must
then use a combination of fork() and for example waitpid() commands.
If you need a sample, query on the list.

Re: [Dev-C++] Re: execution of a string with system()

[Bob W. <bo...@af...>]

Can anyone give an example of this?

Christophe Chailloleau wrote:

>--clip--
>
>Before ending, a little warning : if you want to execute system commands in
>a multi-threaded program, you MUSN'T use the system() function. You must
>then use a combination of fork() and for example waitpid() commands.
>If you need a sample, query on the list.
>
>--clip==
>

-- 
	-- Bob

' Sally:"So a man can be friends with a woman he finds unattractive?" Harry:"No, you pretty much want to nail them, too" '

ICQ: 77149742
AOL: Sanchrin
MSN: Bo...@af...
http://www.aftermath.cx/

Re: [Dev-C++] Re: execution of a string with system()

[Abhijit S. <mu...@gm...>]

>
> Hello,
>
> think Abhijit Shylanath mistyped his response - should be (untested too) :
>

Yes, he did. Dumb guy. Serves him right for mixing up ambiguity.

...

> Before ending, a little warning : if you want to execute system commands
in
> a multi-threaded program, you MUSN'T use the system() function. You must
> then use a combination of fork() and for example waitpid() commands.
> If you need a sample, query on the list.

This is, unfortunately, platform-dependant, and on Windows, you should use
CreateProcess(). Same last sentence.

___________________________________________________________

Abhijit Shylanath

E-mail:   mu...@gm... || ibr...@bi...
Web-site: http://mudeth.tripod.com/