Function pseudoPinsSetup

wiringPi/pseudoPins.c:76–110

int pseudoPinsSetup(const int pinBase)
{
    struct wiringPiNodeStruct *node;
    void *ptr;

    node = wiringPiNewNode(pinBase, PSEUDO_PINS);
    if (node == NULL) {
      fprintf(stderr, "Error creating new wiringPi node");
      return false;
    }

    node->fd = shm_open(SHARED_NAME, O_CREAT | O_RDWR, 0666);
    if (node->fd < 0) {
      perror("Error opening shared memory");
      return false;
    }

    if (ftruncate(node->fd, PSEUDO_PINS * sizeof(int)) < 0) {
      perror("Error resizing shared memory");
      return false;
    }

    ptr = mmap(NULL, PSEUDO_PINS * sizeof(int), PROT_READ | PROT_WRITE, MAP_SHARED, node->fd, 0);
    if (ptr == MAP_FAILED) {
      perror("Error mapping shared memory");
      return false;
    }

    node->data0 = (unsigned int)(uintptr_t)ptr;

    node->analogRead = myAnalogRead;
    node->analogWrite = myAnalogWrite;

    return true;
}