c - Making a void* within a struct point to an integer -

i have struct follows:

typedef struct node {     void* data;     unsigned long id;     nodeptr next;     nodeptr prev; } node; 

it meant node in linked list adt. have 2 different constructors depending on node needs hold in data. 1 constructor uses:

nodeptr tempnode; tempnode = malloc( sizeof(node) ); /* other stuff */ tempnode->data = newlist(); return (tempnode); 

and seems work fine letting me access list returning (list->current->data) current node pointer in list struct

however, want make version of constructor (data) points int. i've read can doing following

void* ptr; int x = 0; *((int*)ptr) = x; 

but way constructor set up, mean have this?

*((int*)tempnode->data) = 1; // data starts @ 1 

and doesn't work. i'm new c don't understand of terminology. read dereferencing (using -> notation?) cannot done void*'s, seems work fine in list version of constructor. how can rewrite other constructor cast void* int?

i counsel against doing this, if want use void * member hold integer, can do:

node *constructor_int(int n) {     node *tmp = malloc(sizeof(*tmp));     /* other stuff */     tmp->data = (void *)n;     return(tmp); } 

this involves minimum number of casts , avoids problems relative sizes of types.

the obvious, logical way allocate integer data member point at:

node *constructor_int(int n) {     node *tmp = malloc(sizeof(*tmp));     /* other stuff */     tmp->data = malloc(sizeof(int));     *(int *)temp->data = n;     return(tmp); } 

you have remember free 2 memory allocations.

the code should check memory allocations succeeded before using results.