Run-time error when using memset

Question

I am new to C and I am using memset. From what I read memset replaces part of a section of memory with a char. When I try to do that my program shuts down and using breakpoints it stops after the line with memset. Not really sure why.

void init_TCB (struct TCB_t *tcb, void *function, void *stackP, int stack_size)
{
    memset(tcb, '\0', sizeof(struct TCB_t));
    getcontext(&tcb->context);
    tcb->context.uc_stack.ss_sp = stackP;
    tcb->context.uc_stack.ss_size = (size_t)stack_size;
    makecontext(&tcb->context, function, 0);
}

the sizeof(struct TCB_t) is 957, tcb is the memory location for the struct, and '\0' is a char.

Here is the struct `

struct TCB_t
{
struct TCB_t * next;
struct TCB_t * previous;
ucontext_t context;
};

and here is where I initialize the struct

void start_thread(void (*function)(void))
{
struct stack * stackP = (struct stack*)malloc(sizeof(struct stack));
struct TCB_t * tcb = (struct TCB_t *)(sizeof(struct TCB_t));
init_TCB (tcb, function, stackP,  8192);
ptr = create_list();
add_to_list( ptr);

}

Answer 1

This line is wrong:

struct TCB_t * tcb = (struct TCB_t *)(sizeof(struct TCB_t));

You're pointing tcb to the size of the structure.

Instead you could allocate space for the structure with malloc():

struct TCB_t * tcb = malloc(sizeof(struct TCB_t));