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Hello everybody,

I'm trying to program a linked list, but unfortunately it segfaults when
I run the program. The code is basically the same as one can find in
several places in the internet. With gdb I found out, that my root->next
points to some strange memory area instead of where it should.

The program segfaults in the while loop in list_append during the third
call of list_append.

Can somebody help me? I'll also gladly send the whole code and Makefile
to somebody personally if he/she's willing to look at it.

Thanks,
Alex

Here's my code:

===== stl.h =====

typedef struct {
float x, y, z;
} point;

typedef struct {
point n;
point v1;
point v2;
point v3;
} triangle;

typedef struct node *nodeptr;

typedef struct node{
triangle tri;
nodeptr next; //Zeiger auf einen Listenknoten
} node;

void list_append(nodeptr node);




===== list.c =====

#include "stl.h"

nodeptr root = NULL;

void list_append(nodeptr node)
{
nodeptr cur_node;

if(root == NULL){
root = node;
root->next= NULL;
} else {
cur_node = root;
while (cur_node->next != NULL)
cur_node = cur_node->next;
cur_node->next = node;
cur_node = cur_node->next;
cur_node->next = NULL;
}
}



===== main.c =====

nodeptr cur_triangle

for(i = 1; i < number_of_triangles; i++)
{
// Values are being read into temptriangle array
cur_triangle = (nodeptr) malloc(sizeof(nodeptr));
cur_triangle->tri.n.x = temptriangle[0];
cur_triangle->tri.n.y = temptriangle[1];
cur_triangle->tri.n.z = temptriangle[2];
cur_triangle->tri.v1.x = temptriangle[3];
cur_triangle->tri.v1.y = temptriangle[4];
cur_triangle->tri.v1.z = temptriangle[5];
cur_triangle->tri.v2.x = temptriangle[6];
cur_triangle->tri.v2.y = temptriangle[7];
cur_triangle->tri.v2.z = temptriangle[8];
cur_triangle->tri.v3.x = temptriangle[9];
cur_triangle->tri.v3.y = temptriangle[10];
cur_triangle->tri.v3.z = temptriangle[11];

list_append(cur_triangle);
}

Has nothing to do with C
"Alexander Hunziker" <> wrote in message
news: ...
> Hello everybody,
>
> I'm trying to program a linked list, but unfortunately it segfaults when
> I run the program. The code is basically the same as one can find in
> several places in the internet. With gdb I found out, that my root->next
> points to some strange memory area instead of where it should.
>
> The program segfaults in the while loop in list_append during the third
> call of list_append.
>
> Can somebody help me? I'll also gladly send the whole code and Makefile
> to somebody personally if he/she's willing to look at it.
>
> Thanks,
> Alex
>
> Here's my code:
>
> ===== stl.h =====
>
> typedef struct {
> float x, y, z;
> } point;
>
> typedef struct {
> point n;
> point v1;
> point v2;
> point v3;
> } triangle;
>
> typedef struct node *nodeptr;
>
> typedef struct node{
> triangle tri;
> nodeptr next; //Zeiger auf einen Listenknoten
> } node;
>
> void list_append(nodeptr node);
>
>
>
>
> ===== list.c =====
>
> #include "stl.h"
>
> nodeptr root = NULL;
>
> void list_append(nodeptr node)
> {
> nodeptr cur_node;
>
> if(root == NULL){
> root = node;
> root->next= NULL;
> } else {
> cur_node = root;
> while (cur_node->next != NULL)
> cur_node = cur_node->next;
> cur_node->next = node;
> cur_node = cur_node->next;
> cur_node->next = NULL;
> }
> }
>
>
>
> ===== main.c =====
>
> nodeptr cur_triangle
>
> for(i = 1; i < number_of_triangles; i++)
> {
> // Values are being read into temptriangle array
> cur_triangle = (nodeptr) malloc(sizeof(nodeptr));
> cur_triangle->tri.n.x = temptriangle[0];
> cur_triangle->tri.n.y = temptriangle[1];
> cur_triangle->tri.n.z = temptriangle[2];
> cur_triangle->tri.v1.x = temptriangle[3];
> cur_triangle->tri.v1.y = temptriangle[4];
> cur_triangle->tri.v1.z = temptriangle[5];
> cur_triangle->tri.v2.x = temptriangle[6];
> cur_triangle->tri.v2.y = temptriangle[7];
> cur_triangle->tri.v2.z = temptriangle[8];
> cur_triangle->tri.v3.x = temptriangle[9];
> cur_triangle->tri.v3.y = temptriangle[10];
> cur_triangle->tri.v3.z = temptriangle[11];
>
> list_append(cur_triangle);
> }
>

"BGreene" <> writes:
> Has nothing to do with C
> "Alexander Hunziker" <> wrote in message
> news: ...
>> Hello everybody,
>>
>> I'm trying to program a linked list, but unfortunately it segfaults when
>> I run the program. The code is basically the same as one can find in
>> several places in the internet. With gdb I found out, that my root->next
>> points to some strange memory area instead of where it should.
[...]

First, please don't top-post.

Second, what makes you think the question has nothing to do with C?

Third, we answered the OP's question several days ago (the problem was
an incorrect argument to malloc()).

--
Keith Thompson (The_Other_Keith) kst- <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.