Btukfyl

I'm trying to generate a tree of threads, in which each thread creates two more and so on. Reached the tree end (command line arg) I need to print the branch backwards.

I gave up using malloc and similar because I was getting lost in the errors and I'm now working with fixed sized arrays. But still I get segfault errors and even using valgrind is not really helping.
In theory I should be able to do this only using pthread_create (with no attributes) but I'm getting very confused, can you help me figure out where the memory leaks are happening?
Valgrind results mostly include the "copy from tS" lines, but I don't understand where the issue would be.

I'm really not an expert so I wouldn't exclude to be making some stupid mistake, thank you for the patience.

I attach the code

#include <stdio.h>

#include <unistd.h>

#include <pthread.h>

#include <stdlib.h>

#include <math.h>



int maxDepth;



typedef struct {

    int d;

    pthread_t *b;

} tS;



void *tF (void *svp) {

    tS *sp, s, t[2];

    int d, i;

    pthread_t branch[maxDepth], mythread;



    /*get the struct*/

    sp = (tS *) svp;

    s = *sp;



    /*copy tS values*/

    d=s.d;

    for (i =0; i< d; i++) {

        branch[i]=s.b[i];

    }



    /*iterate or print*/

    if (d < maxDepth) {

        for (i=0; i<2; i++) {

            t[i].d = d+1;

            t[i].b = branch;

            t[i].b[d] = pthread_self();

            pthread_create(&mythread, NULL, tF, (void *) &t[i]);

        }

    } else {

        printf("Thread tree: ");

        for (i =0; i< maxDepth; i++) {

            printf("%ld ", branch[i]);

        }

        putchar('n');

    }



    pthread_exit(NULL);

}



int main(int argc, char **argv) {

    maxDepth = atoi(argv[1]);



    int i;

    pthread_t branch[maxDepth];

    pthread_t mythread;

    tS t[2];



    for (i=0; i<2; i++) {

        t[i].d = 1;

        t[i].b= branch;

        t[i].b[0] = pthread_self(); 

        pthread_create(&mythread, NULL, tF, (void *) &t[i]);

    }

    pthread_exit(NULL);

    return 0;



}

One problem is

tS t[2];

pthread_t  branch[maxDepth];

are local variable and will destroyed once control exits the function since you don't have join anywhere.

And you are passing the same variables as argument to pthread_create().

  for (i=0; i<2; i++) {

            t[i].d = d+1;

            t[i].b = branch;  // Here

            t[i].b[d] = pthread_self();

            pthread_create(&mythread, NULL, tF, (void *) &t[i]); //and here

        }

What you can try is dynamically allocate.

   tS *t = malloc(sizoeof(*t)*2);

   t[i].b = malloc(sizeof(pthread_t)*maxDepth);