From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Steve Graegert" <graegerts@gmail.com>
Subject: Re: execv fails with EFAULT
Date: Wed, 7 Mar 2007 14:50:53 +0100
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To: Prasanta Sadhukhan <Prasanta.Sadhukhan@sun.com>
Cc: linux-c-programming@vger.kernel.org

On 3/7/07, Prasanta Sadhukhan <Prasanta.Sadhukhan@sun.com> wrote:
> Steve Graegert wrote:
>
> > On 3/7/07, Prasanta Sadhukhan <Prasanta.Sadhukhan@sun.com> wrote:
> >
> >> Hi,
> >>
> >> When I tried the following program
> >> void test4()
> >> {
> >>     printf("doing execv\n");
> >>     if(execv("/bin/ls", "-l") =3D=3D -1)
> >>         printf("exec failed with errno %d\n", errno);
> >>     else
> >>         printf("exec succeed\n");
> >> }
> >
> >
> > Prasanta,
> >
> > A NULL terminated array of arguments must be passed to execv(2) as =
the
> > prototype indicates: int execv(const char *path, char *const argv[]=
);
> >
> > For example:
> >
> > #include <unistd.h>
> >
> > char *cmd[] =3D { "ls", "-l", NULL };
> > int result =3D execv ("/bin/ls", cmd);
> >
> > An error of EFAULT usually means that an argument points to an ille=
gal
> > address.
> >
> >     \Steve
>
> Thanks Steve... If I have a string like this sprintf(str,
> "-Xparameter:%d %s, value, command"), how to make it NULL terminated.=
 Is
> this declaration char *cmd[] =3D {str, NULL} and invocation
> execv(path, cmd) correct?

If you mean

        sprintf(str, "-Xparameter:%d %s", value, command);

your declaration and invocation of

        char *cmd[] =3D {str, NULL}
        execv(path, cmd);

should be OK.

	\Steve

--

Steve Gr=E4gert <steve@graegert.com>
Jabber    xmpp://graegerts@jabber.org
Internet  http://eth0.graegert.com, http://blog.graegert.com
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