Question

I have no experience in C, but…

If I wanted to write a program, in C, for a linux system, that would sync a local file/directory to a remote file/directory, automatically when the local file/directory is updated; what libraries or built-ins should I look at?

I looked at inotify so far, but I really lack the terminology to search for this without some help.

Edit

This is merely an exercise.

Answer 1

inotify‘s the way to go. Struggle through it, when you get stuck come back and ask more specific questions here.

Here’s an example to get you started (excuse the C++ output statements, imagine printf instead):

void waitfor_activity(const char *path)
{
        const int fd = inotify_init();
        const int wd = inotify_add_watch(fd, path, IN_MODIFY | IN_CLOSE_WRITE);

        char buffer[EVENT_BUF_LEN];
        while (true)
        {
                const ssize_t length = read(fd, buffer, EVENT_BUF_LEN); 
                if (length < 0) {
                        perror("read");
                }  
                const struct inotify_event *event = ( struct inotify_event * ) buffer;
                std::cout << "event: ";
                if (event->mask & IN_CLOSE_WRITE)
                {
                        std::cout << "IN_CLOSE_WRITE ";
                }
                if (event->mask & IN_MODIFY)
                {
                        std::cout << "IN_MODIFY ";
                }
                std::cout << std::endl;
        }
        close(fd);
}