How to change character string in function call?

[Wavelet]

I want have one string array and want to assign them in
one sub-function. After that,it will be used in main funcion.
But it seems the following code doesn't work.How can I
do it with pointer?

#include <stdio.h>
#include <stdlib.h>

char *str[] = {"word1","word2"};
void sub(char **p)
{

p = str;

}
main()
{
char** argv= NULL;
sub(&argv);
printf("arg[0]=%s\n",argv);
printf("arg[1]=%s\n",argv+1);
}

=========Result=======
[linuxred@vike tmp]$ a.out
arg[0]=(null)
Segmentation fault

 

[Wavelet]

#include <stdio.h>
#include <stdlib.h>
I found this version works. But too complex argument.

void sub(char ***p)
{
char str[100][100];
strcpy(str[0],"word1");
strcpy(str[1],"word2");

char ***q;
*p = str[0];
*(p+1) = str[1];

}
main()
{
char* argv[100];
sub(&argv);
printf("arg[0]=%s\n",argv[0]);
printf("arg[1]=%s\n",argv[1]);
}

 

[Richard Bos]

I want have one string array and want to assign them in
one sub-function. After that,it will be used in main funcion.
But it seems the following code doesn't work.How can I
do it with pointer?

#include <stdio.h>
#include <stdlib.h>

char *str[] = {"word1","word2"};
void sub(char **p)
{

p = str;

}

<http://c-faq.com/aryptr/pass2dary.html>
<http://c-faq.com/aryptr/ary2dfunc2.html>
<http://c-faq.com/ptrs/passptrinit.html>

Not a complete answer, but that should set you on the right track at
least.

Richard

 

[xdevel]

Wavelet ha scritto:

I found this version works. But too complex argument.

try this:

void sub(char **p)
{
*p = *str;
p++;
*p = *(str+1);
}


in main()

char *argv[2];
sub(argv);
printf("arg[0]=%s\n",*argv);
printf("arg[1]=%s\n",*(argv+1));

 

[Fred Kleinschmidt]

I want have one string array and want to assign them in
one sub-function. After that,it will be used in main funcion.
But it seems the following code doesn't work.How can I
do it with pointer?

#include <stdio.h>
#include <stdlib.h>

char *str[] = {"word1","word2"};
void sub(char **p)
{

p = str;

}
main()
{
char** argv= NULL;
sub(&argv);
printf("arg[0]=%s\n",argv);
printf("arg[1]=%s\n",argv+1);
}

#include <stdio.h>

char *str[] = {"word1","word2"};
void sub(char ***p)
{
*p = str;
}

int main() {
char** argv;
sub(&argv);
printf("arg[0]=%s\n",argv[0]);
printf("arg[1]=%s\n",argv[1]);
return 0;
}

=========Result=======
[linuxred@vike tmp]$ a.out
arg[0]=(null)
Segmentation fault