program dies after swapcontext()

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First time I am working with ucontext_t. My program dies after I call first swapcontext(). The program prints out the function I called, but then does nothing else.

struct TCB_t  *RunQ;

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


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);

}

static void functionOne()
{
puts("start f1");

puts("finish f1");
}


void start_thread(void (*function)(void))
{
    struct stack * stackP = (struct stack*)malloc(sizeof(struct stack));
    struct TCB_t * tcb = (struct TCB_t *)malloc(sizeof(struct TCB_t));
    init_TCB (tcb, function, stackP,  8192);
    RunQ = tcb;
}


void run()
{
     ucontext_t parent;
     getcontext(&parent);
     printf("\n -------Printing list Start-2------ \n");
     swapcontext(&parent, &(RunQ->context));
     printf("\n -------Printing list Start-4------ \n");
}
int main(void)
{

start_thread(functionOne);
run();
}

The output I get is -------Printing list Start-2------ start f1 finish f1 So it swapcontext() and dies. Is there a next step I am missing?

asked 1 min ago

Aaron

769

program dies after swapcontext()