Memory allocation for Structure Pointer within Structure Pointer

[djcm75]

typedef struct siblings {
char sibname[20];
char gender;
}sib;


typedef struct employee {
char empid[10];
char empname[20];
char status;
float sal;
sib ** s;
}emp;

typedef struct stackemp {
int size;
int ptrPos;
emp ** e;
}stack;

function myfunction(stac k * s) {
(s->e[s->size]) = (emp *) malloc(sizeof(e mp)); //this line works without any errors

(s->e[s->size]->s[0]) = (sib *)malloc(sizeof (sib)); //this line displays segmenation fault during run time
.....
....
}

This code compiles without errors but displays "Segmentati on Fault" during runtime. How do I assign memory for the double pointer 's'

[weaknessforcats]

Where are you allocating s->e ?

That is, I don't see where you are allocating an array of emp*. Not doing that makes e[s->size] invalid.

[johny10151981]

to add note with weaknessforcats

s->e[[B]s->size[/B]]->s[0]

The length of e is s->size; and remember in c/c++ array always start with zero and end in length-1, i.e. in here s->size-1; s->size th point is definitely invalid

[djcm75]

I did not post my entire code

allocation for s->e ? complies & runs perfectly

s->e[s->size] = (emp *)malloc(sizeof (emp));
//where s->size has already been incremented

I am having problem only with
(s->e[s->size]->s[0]) = (sib *)malloc(sizeof (sib));
no compilation during run time i get sementation fault

[weaknessforcats]

malloc(sizeof(s ib)) should allocate 4 bytes on a 32-bit OS since sib is a pointer.

[donbock]

Do you verify that none of your malloc calls returned NULL?
You shouldn't dereference any pointer until you have reason to believe it is not NULL.

[djcm75]

Solved

typedef struct siblings {
char sibname[20];
char gender;
}sib;


typedef struct employee {
char empid[10];
char empname[20];
char status;
float sal;
sib ** s;
}emp;

typedef struct stackemp {
int size;
int ptrPos;
emp ** e;
}stack;

function myfunction(stac k * s) {
(s->e[s->size]) = (emp *) malloc(sizeof(e mp)); //this line works without any errors

(s->e[s->size]->s) = malloc(sizeof(s->e[s->size]->s[0]));
(s->e[s->size]->s[0]) = malloc(sizeof(s ib));
(s->e[s->size]->s[1]) = malloc(sizeof(s ib));

.....
....
}