incorrect method signature and call - c

Question

So I have a program which is supposed to have consumer and producer threads.
In the main method, I want to call init_consumers() which will call ptread_init()
Here is some code:
int init_consumers(char *quantity, pthread_t **cons, void *complex_obj)
{
//seting the limit acording to "quantity"
for (; i < limit; i++)
pthread_create(cons[i], NULL, &consumer, &complex_obj);
return(i);
}
the main:
#include <pthread.h>
#define MAX_PROD 50
#define MAX_CONS 50
///main entry point of the program
int main(int argc, char *argv[])
{
pthread_t prod[MAX_PROD];
pthread_t cons[MAX_CONS];
struct complex_obj *co;
//some code
co = create_cplx_obj();
//complex object manipulation code
init_producers(argv[2], &prod, co);
init_consumers(argv[3], &cons, co);
//more code
exit(0);
}
argv[2] and argv[3] is how many producers/consumers the user wants.
Also, the thread signature is: void *producer(void *args);
I still get problems with the * and &, so my problem is when making the method call and signature.
The error I was getting was
n_prod_n_cons.c:158:6: note: expected ‘pthread_t * {aka long unsigned int *}’ but argument is of type ‘pthread_t (*)[50] {aka long unsigned int (*)[50]}’ int init_producers(char *quantity, pthread_t *prod, void *complex_obj)

Answer 1

As indicated (tersely) in my comment, you have arrays of pthread_t in main(); pass them to the launchers just as you would an array of int. Make the signature of the launcher functions match what you'd do if you passed an array of int. Then use &array[index] to pass a pointer to a single row of the array to pthread_create(). That adds up to:
In main():
init_producers(argv[2], prod, co);
init_consumers(argv[3], cons, co);
(Your code was passing a pthread_t (*)[MAX_PROD] — pointer to a fixed size array of pthread_t — to the launcher functions, quite different from the signatures which expected a pthread_t **.)
The launchers look like:
int init_consumers(char *quantity, pthread_t *cons, void *complex_obj)
{
// setting the limit acording to "quantity"
for (; i < limit; i++)
pthread_create(&cons[i], NULL, consumer, &complex_obj);
return(i);
}
cons[i] is the ith entry in the array of pthread_t; passing its address give the pthread_create() function the pthread_t * it expects.