int uORB::Manager::orb_exists(const struct orb_metadata *meta, int instance)
{
/*
* Generate the path to the node and try to open it.
*/
char path[orb_maxpath];
int inst = instance;
int ret = uORB::Utils::node_mkpath(path, meta, &inst);
if (ret != OK) {
errno = -ret;
return PX4_ERROR;
}
#if defined(__PX4_NUTTX)
struct stat buffer;
ret = stat(path, &buffer);
#else
ret = px4_access(path, F_OK);
#ifdef ORB_COMMUNICATOR
if (ret == -1 && meta != nullptr && !_remote_topics.empty()) {
ret = (_remote_topics.find(meta->o_name) != _remote_topics.end()) ? OK : PX4_ERROR;
}
#endif /* ORB_COMMUNICATOR */
#endif
if (ret == 0) {
// we know the topic exists, but it's not necessarily advertised/published yet (for example
// if there is only a subscriber)
// The open() will not lead to memory allocations.
int fd = px4_open(path, 0);
if (fd >= 0) {
unsigned long is_published;
if (px4_ioctl(fd, ORBIOCISPUBLISHED, (unsigned long)&is_published) == 0) {
if (!is_published) {
ret = PX4_ERROR;
}
}
px4_close(fd);
}
}
return ret;
}
int uORB::Manager::orb_exists(const struct orb_metadata *meta, int instance)
{
/*
* Generate the path to the node and try to open it.
*/
char path[orb_maxpath];
int inst = instance;
int ret = uORB::Utils::node_mkpath(path, PUBSUB, meta, &inst);
if (ret != OK) {
errno = -ret;
return ERROR;
}
return px4_access(path, F_OK);
}