diff --git a/_demo/netdb/netdb.go b/_demo/netdbdemo/netdb.go
similarity index 82%
rename from _demo/netdb/netdb.go
rename to _demo/netdbdemo/netdb.go
index 879ba3e8..f8da4aa0 100644
--- a/_demo/netdb/netdb.go
+++ b/_demo/netdbdemo/netdb.go
@@ -7,8 +7,8 @@ import (
 
 func main() {
 	var hints net.AddrInfo
-	hints.AiFamily = net.AF_UNSPEC
-	hints.AiSockType = net.SOCK_STREAM
+	hints.Family = net.AF_UNSPEC
+	hints.SockType = net.SOCK_STREAM
 
 	host := "httpbin.org"
 	port := "80"
diff --git a/_demo/select/select.go b/c/sys/_demo/selectdemo/select.go
similarity index 87%
rename from _demo/select/select.go
rename to c/sys/_demo/selectdemo/select.go
index 918150f8..eaff1c80 100644
--- a/_demo/select/select.go
+++ b/c/sys/_demo/selectdemo/select.go
@@ -1,23 +1,21 @@
 package main
 
 import (
+	"unsafe"
+
 	"github.com/goplus/llgo/c"
 	"github.com/goplus/llgo/c/os"
 	"github.com/goplus/llgo/c/sys"
-	"github.com/goplus/llgo/c/syscall"
-	"unsafe"
 )
 
 func main() {
-	var readFds syscall.FdSet
-
+	var readFds sys.FdSet
 	sys.FD_ZERO(&readFds)
-
 	sys.FD_SET(0, &readFds)
 
-	var tv sys.TimeVal
-	tv.TvSec = 5
-	tv.TvUSec = 0
+	var tv sys.Timeval
+	tv.Sec = 5
+	tv.Usec = 0
 
 	c.Printf(c.Str("Waiting for input on stdin...\n"))
 	ret := sys.Select(1, &readFds, nil, nil, &tv)
diff --git a/_demo/select/select2.go b/c/sys/_demo/selectdemo2/select2.go
similarity index 93%
rename from _demo/select/select2.go
rename to c/sys/_demo/selectdemo2/select2.go
index 68069d1e..ada4418a 100644
--- a/_demo/select/select2.go
+++ b/c/sys/_demo/selectdemo2/select2.go
@@ -1,12 +1,12 @@
 package main
 
 import (
+	"unsafe"
+
 	"github.com/goplus/llgo/c"
 	"github.com/goplus/llgo/c/net"
 	"github.com/goplus/llgo/c/os"
 	"github.com/goplus/llgo/c/sys"
-	"github.com/goplus/llgo/c/syscall"
-	"unsafe"
 )
 
 const (
@@ -41,14 +41,15 @@ func main() {
 		return
 	}
 
-	var writefds, readfds syscall.FdSet
-	var timeout sys.TimeVal
+	var writefds, readfds sys.FdSet
+	var timeout sys.Timeval
 
 	//  Monitor socket writes
 	sys.FD_ZERO(&writefds)
 	sys.FD_SET(sock, &writefds)
-	timeout.TvSec = 10
-	timeout.TvUSec = 0
+	timeout.Sec = 10
+	timeout.Usec = 0
+
 	// Use select to monitor the readiness of writes
 	if sys.Select(sock+1, nil, &writefds, nil, &timeout) > 0 {
 		if sys.FD_ISSET(sock, &writefds) != 0 {