Woes with C (incompatible assignment...and threads).

Turner

deleted.

telcus

What's your code for creating ready_trains?
Dynamic arrays need to be malloc'ed before they can be used as arrays.

Bob Sapp

Looks like you're trying to assign a train pointer when the array holds trains, not pointers. I'm making the assumption that the array is dynamically allocated. Try ready_trains[numreadytrains] = *traintest;

falsedef

ready_trains[numreadytrains] = traintest

should be


ready_trains = traintest


assuming both are arrays

Doc

Bob Sapp wrote: »

Looks like you're trying to assign a train pointer when the array holds trains, not pointers. I'm making the assumption that the array is dynamically allocated. Try ready_trains[numreadytrains] = *traintest;

this

telcus

I think the problem may be that ready_trains is a dynamic array of train structs, where as traintest is a pointer to a train struct.

What you want is ready_trains to be a dynamic array of pointers to train structs

train **ready_trains, and malloc accordingly.

God C is a confusing language.

falsedef

Doc wrote: »

Bob Sapp wrote: »

Looks like you're trying to assign a train pointer when the array holds trains, not pointers. I'm making the assumption that the array is dynamically allocated. Try ready_trains[numreadytrains] = *traintest;

this

That looks like a buffer overflow.

Turner

deleted.

falsedef

I looked at all of your code this time. If you're trying to pass by pointer instead of copy:

This part in your thread creator area:

train *temp;
        temp = (pthread_t *) malloc(sizeof(pthread_t)*numtrains);

as I see is suppose to look more like:

train *temp; // temp pointer
numreadytrains = 0; // the global scope current index
ready_trains = (train *) malloc(sizeof(train)*numtrains); // allocate space for global scope ready trains

Because temp is being assigned within your loop, you don't need to allocate it individually:

pthread_create(&control , NULL, Control, NULL);
                for(j = 0; j < numtrains; j++)  {
                        temp = &(train_array[j]); // pass the address of the train at index j
                        pthread_create(&train_array[j].thread, NULL, Train, (void *)temp);
                }

Then you can use the fix Bob Sapp gave you. At the moment, if you use Bob's code without the changes, it looks like you're allocating temp instead of allocating readytrains to the appropriate size, which might segfault or give bad data.

Turner

deleted.