Get /dev/disk/by-id element from /dev/sd* element

I know that there is /dev/disk/by-id/ folder which contains links to /dev/sd* elements. I'd like to know, is there any way to get by-id element pointing to, for example, /dev/sda.

P.S.: yeah, I know that I can loop through elements in by-id folder and /dev/sd*, so that I can compare serial numbers and match them. But is there any better way?

EDIT: sorry for my mistake. It should be done in C/C++. UUID's were mentioned. That would be great, they are unique and so on, but how can I collect all the UUID's of one hdd? I mean the main, pointing to sda, for example, and partition UUID's, pointing to sda1, sda2 and so on.

I'm sorry for late answer.

My question was wrong, I did not need /dev/sd* element to get /dev/disk/by-id/ elements.

I've used libudev and got these elements:

#include <libudev.h>

...

struct udev *udev;
udev = udev_new();

udev_enumerate *enumerate;
enumerate = udev_enumerate_new(udev);

udev_list_entry *udev_entries;
udev_list_entry *dev_list_entry;
udev_device *dev;

udev_enumerate_add_match_subsystem(enumerate, "block");
udev_enumerate_scan_devices(enumerate);
udev_entries = udev_enumerate_get_list_entry(enumerate);
udev_list_entry_foreach(dev_list_entry, udev_entries)
{
    const char* path = udev_list_entry_get_name(dev_list_entry);
    dev = udev_device_new_from_syspath(udev, path);
    const char* bus = udev_device_get_property_value(dev, "ID_BUS");
    const char* type = udev_device_get_property_value(dev, "ID_TYPE");

    if (!bus || !type)
        continue;

    // strncmp return 0 if equal
    if (!(strncmp(bus, "ata", 3) &&
            !strncmp(type, "disk", 4))
        continue;

    // i wanted to get only partitions, so parent is empty
    udev_device *parent = 
        udev_device_get_parent_with_subsystem_devtype(dev, "block", "disk");
    if (!parent)
        continue;

    // get /dev/disk/by-id/...-partX
    struct udev_list_entry* devlinks = udev_device_get_devlinks_list_entry(dev);
    std::string partition(udev_list_entry_get_name(devlinks));
    // now we have /dev/disk/by-id/...-partX in partition and can save it somewhere
}

P.S.: I've used that in special LFS-based distribution, that does have serial numbers in /dev/disk/by-id/ name.