symlink?

/*
 * call-seq:
 *   File.symlink?(file_name)   =>  true or false
 *
 * Returns <code>true</code> if the named file is a symbolic link.
 */

static VALUE
test_l(obj, fname)
    VALUE obj, fname;
{
#ifndef S_ISLNK
#  ifdef _S_ISLNK
#    define S_ISLNK(m) _S_ISLNK(m)
#  elif defined __BORLANDC__
#    ifdef _S_IFLNK
#      define S_ISLNK(m) (((unsigned short)(m) & S_IFMT) == _S_IFLNK)
#    else
#      ifdef S_IFLNK
#        define S_ISLNK(m) (((unsigned short)(m) & S_IFMT) == S_IFLNK)
#      endif
#    endif
#  else
#    ifdef _S_IFLNK
#      define S_ISLNK(m) ((m & S_IFMT) == _S_IFLNK)
#    else
#      ifdef S_IFLNK
#        define S_ISLNK(m) ((m & S_IFMT) == S_IFLNK)
#      endif
#    endif
#  endif
#endif

#ifdef S_ISLNK
    struct stat st;

    SafeStringValue(fname);
    if (lstat(StringValueCStr(fname), &st) < 0) return Qfalse;
    if (S_ISLNK(st.st_mode)) return Qtrue;
#endif

    return Qfalse;
}