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READLINK(2)                 BSD System Calls Manual                READLINK(2)

     readlink, readlinkat -- read value of a symbolic link

     #include <&lt;unistd.h>&gt;

     readlink(const char *restrict path, char *restrict buf, size_t bufsiz);

     #include <&lt;fcntl.h>&gt;
     #include <&lt;unistd.h>&gt;

     readlinkat(int fd, const char *path, char *buf, size_t bufsiz);

     The readlink() function places the contents of the symbolic link path in
     the buffer buf, which has size bufsiz.  readlink does not append a NUL
     character to buf.

     The readlinkat() function is equivalent to readlink() except that where
     path specifies a relative path, the symbolic link whose contents are read
     is determined relative to the directory associated with file descriptor
     fd instead of the current working directory.

     If readlinkat() is passed the special value AT_FDCWD (defined in
     <fcntl.h>) in the fd parameter, the current working directory is used and
     the behavior is identical to a call to readlink().

     The call returns the count of characters placed in the buffer if it suc-
     ceeds, or a -1 if an error occurs, placing the error code in the global
     variable errno.

     readlink() and readlinkat() will fail if:

     [ENOTDIR]          A component of the path prefix is not a directory.

     [ENAMETOOLONG]     A component of a pathname exceeded NAME_MAX charac-
                        ters, or an entire pathname (including the terminating
                        NUL) exceeded PATH_MAX bytes.

     [ENOENT]           The named file does not exist.

     [EACCES]           Search permission is denied for a component of the
                        path prefix.

     [ELOOP]            Too many symbolic links were encountered in translat-
                        ing the pathname.

     [EINVAL]           The named file is not a symbolic link.

     [EIO]              An I/O error occurred while reading from the file sys-

     [EFAULT]           buf or path extends outside the process's allocated
                        address space.

     Additionally, readlinkat() will fail if:

     [EBADF]            The path argument specifies a relative path and the fd
                        argument is neither AT_FDCWD nor a valid file descrip-

     [ENOTDIR]          The path argument specifies a relative path and the fd
                        argument is a valid file descriptor but it does not
                        reference a directory.

     [EACCES]           The path argument specifies a relative path but search
                        permission is denied for the directory which the fd
                        file descriptor references.

     lstat(2), stat(2), symlink(2), symlink(7)

     The readlink() and readlinkat() functions conform to IEEE Std 1003.1-2008

     The readlink() system call first appeared in 4.1cBSD.  The readlinkat()
     system call has been available since OpenBSD 5.0.

BSD                            January 19, 2015                            BSD