Reads the contents of the specified symbolic link and places them
    into a user-supplied buffer.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <unistd.h>

      ssize_t readlink  (const char *restrict link_name, char
                        *restrict user_buffer, size_t buffer_size);

1 - Arguments

 link_name

    Pointer to the text string representing the name of the symbolic
    link file.

 user_buffer

    Pointer to the user buffer.

 buffer_size

    Size of the user buffer.

2 - Description

    The readlink function reads the contents of the specified
    symbolic link (link_name) and places them into a user-supplied
    buffer (user_buffer) of size (buffer_size).

    See also symlink, unlink, realpath, lchown, and lstat.

3 - Return Values

    n                  Upon successful completion, the count of bytes
                       placed in the user_buffer
    -1                 Indicates an error. The buffer is unchanged,
                       and errno is set to indicate the error:

                       o  EACCES - Read permission is denied in the
                          directory where the symbolic link is being
                          read, or search permission is denied for a
                          component of the path prefix of link_name.

                       o  ENAMETOOLONG - The length of the link_name
                          argument exceeds PATH_MAX, or a pathname
                          component is longer than NAME_MAX.

                       o  Any errno value from close, open, or read.