How to check whether a file is locked in Cocoa?

Question

Is there any API to check whether a file is a locked? I am not able to find any API in the NSFileManager class.Let me know if there is any API to check the lock of

Answer 1

I don't really know the answer to this question as I don't know how OS X implements its locking mechanism.

It might use the POSIX advisory locking as documented in the flock() manpage and if I were you I would write a 10 31-line test program in C to show what fcntl() (manpage) thinks about the advisory lock you have made from within Finder.

Something like (untested):

#include 
#include 
#include 

int main(int argc, const char **argv)
{
    for (int i = 1; i < argc; i++)
    {
        const char *filename = argv[i];
        int fd = open(filename, O_RDONLY);
        if (fd >= 0)
        {
            struct flock flock;
            if (fcntl(fd, F_GETLK, &flock) < 0)
            {
                fprintf(stderr, "Failed to get lock info for '%s': %s\n", filename, strerror(errno));
            }
            else
            {
                // Possibly print out other members of flock as well...
                printf("l_type=%d\n", (int)flock.l_type);
            }
            close(fd);
        }
        else
        {
            fprintf(stderr, "Failed to open '%s': %s\n", filename, strerror(errno));
        }
    }
    return 0;
}