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Old 04-09-2007, 06:23 PM   #1
haydari
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Registered: Apr 2007
Posts: 13

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How can I assign to a pointer array like char *args[]; ?


Hi,

I need to assign to an array like char *args[];

for example I have some data as parameters in the *argv[] array.
I need to assign these values starting from argv[1] to argv[argc-1] into the *args[] array.

for (i=1; i<argc; i++)
strcpy(args[i-1], argv[i]);

That doesn't work. Any idea how can I handle this?

Thanks.

Last edited by haydari; 04-09-2007 at 06:26 PM.
 
Old 04-09-2007, 06:55 PM   #2
tuxdev
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Registered: Jul 2005
Distribution: Slackware
Posts: 2,012

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I'm suspecting you need this to call execv. Try
Code:
int i = 0;
char **args = malloc((argc + 1) * sizeof(char *));
while(i < argc) {
   args[i] = argv[i + 1];
   i++;
}
args[argc] = 0;
execv...
If you're adventurous, you can also try
Code:
int i = 0;
while(i < argc) {
   argv[i] = argv[i + 1];
}
execv...
But what you really need to know is that strcpy isn't always appropriate, and direct assignment is okay sometimes.
 
Old 04-09-2007, 07:17 PM   #3
haydari
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Registered: Apr 2007
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Thank you very much, it worked.

Yes, I will use it with execve :=). I have an assignment about creating a shell terminal executing shell commands with parameters, using execve command.

In your code, could you tell me why do I need to use double pointer, **args? And I hope any error won't appear when I use it like execve(pathname, args, NULL); because of it is a double pointer... (I didn't have enough time to check this in the lab, will try it tomorrow..)

Last edited by haydari; 04-09-2007 at 08:01 PM.
 
Old 04-09-2007, 11:48 PM   #4
varun_shrivastava
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Registered: Jun 2006
Distribution: Ubuntu 7.04 Feisty
Posts: 79

Rep: Reputation: 15
Code:
 int execve(const char *filename, char *const argv[],
                  char *const envp[]);
2nd argument is nothing but **args

*argv[] is = to **argv
 
  


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