socket?

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

static VALUE
test_S(obj, fname)
    VALUE obj, fname;
{
#ifndef S_ISSOCK
#  ifdef _S_ISSOCK
#    define S_ISSOCK(m) _S_ISSOCK(m)
#  elif defined __BORLANDC__
#    ifdef _S_IFSOCK
#      define S_ISSOCK(m) (((unsigned short)(m) & S_IFMT) == _S_IFSOCK)
#    else
#      ifdef S_IFSOCK
#        define S_ISSOCK(m) (((unsigned short)(m) & S_IFMT) == S_IFSOCK)
#      endif
#    endif
#  else
#    ifdef _S_IFSOCK
#      define S_ISSOCK(m) ((m & S_IFMT) == _S_IFSOCK)
#    else
#      ifdef S_IFSOCK
#        define S_ISSOCK(m) ((m & S_IFMT) == S_IFSOCK)
#      endif
#    endif
#  endif
#endif

#ifdef S_ISSOCK
    struct stat st;

    if (rb_stat(fname, &st) < 0) return Qfalse;
    if (S_ISSOCK(st.st_mode)) return Qtrue;

#endif
    return Qfalse;
}