diff --git a/c/net/net.go b/c/net/net.go
index c6163c3b..7b2608aa 100644
--- a/c/net/net.go
+++ b/c/net/net.go
@@ -109,17 +109,6 @@ type Hostent struct {
 	AddrList **c.Char // null-terminated array of addresses for the host
 }
 
-type AddrInfo struct {
-	AiFlags     c.Int
-	AiFamily    c.Int
-	AiSockType  c.Int
-	AiProtocol  c.Int
-	AiAddrLen   c.Uint
-	AiCanOnName *c.Char
-	AiAddr      *SockAddr
-	AiNext      *AddrInfo
-}
-
 //go:linkname Socket C.socket
 func Socket(domain c.Int, typ c.Int, protocol c.Int) c.Int
 
@@ -143,14 +132,6 @@ func GetHostByName(name *c.Char) *Hostent
 //go:linkname InetNtop C.inet_ntop
 func InetNtop(af c.Int, src c.Pointer, dst *c.Char, size c.Uint) *c.Char
 
-func SwapInt16(data uint16) uint16 {
-	return (data << 8) | (data >> 8)
-}
-
-func Htons(x uint16) uint16 {
-	return SwapInt16(x)
-}
-
 //go:linkname InetAddr C.inet_addr
 func InetAddr(s *c.Char) c.Uint
 
@@ -160,8 +141,33 @@ func Send(c.Int, c.Pointer, uintptr, c.Int) c.Long
 //go:linkname Recv C.recv
 func Recv(c.Int, c.Pointer, uintptr, c.Int) c.Long
 
+// -----------------------------------------------------------------------------
+
+type AddrInfo struct {
+	Flags     c.Int
+	Family    c.Int
+	SockType  c.Int
+	Protocol  c.Int
+	AddrLen   c.Uint
+	CanOnName *c.Char
+	Addr      *SockAddr
+	Next      *AddrInfo
+}
+
 //go:linkname Getaddrinfo C.getaddrinfo
 func Getaddrinfo(host *c.Char, port *c.Char, addrInfo *AddrInfo, result **AddrInfo) c.Int
 
 //go:linkname Freeaddrinfo C.freeaddrinfo
 func Freeaddrinfo(addrInfo *AddrInfo) c.Int
+
+// -----------------------------------------------------------------------------
+
+func swapInt16(data uint16) uint16 {
+	return (data << 8) | (data >> 8)
+}
+
+func Htons(x uint16) uint16 {
+	return swapInt16(x)
+}
+
+// -----------------------------------------------------------------------------
diff --git a/c/sys/select.go b/c/sys/select.go
index 1b7cc004..7cd7b9ea 100644
--- a/c/sys/select.go
+++ b/c/sys/select.go
@@ -1,10 +1,10 @@
 package sys
 
 import (
-	"github.com/goplus/llgo/c/syscall"
 	_ "unsafe"
 
 	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/syscall"
 )
 
 const (
@@ -12,12 +12,6 @@ const (
 	LLGoPackage = "link"
 )
 
-// (TODO) merge to timeval
-type TimeVal struct {
-	TvSec  c.Long
-	TvUSec c.Int
-}
-
 //go:linkname FD_ZERO C.fd_zero
 func FD_ZERO(fdSet *syscall.FdSet)
 
@@ -28,4 +22,4 @@ func FD_SET(fd c.Int, fdSet *syscall.FdSet)
 func FD_ISSET(fd c.Int, fdSet *syscall.FdSet) c.Int
 
 //go:linkname Select C.select
-func Select(n c.Int, r *syscall.FdSet, w *syscall.FdSet, e *syscall.FdSet, timeout *TimeVal) c.Int
+func Select(n c.Int, r *syscall.FdSet, w *syscall.FdSet, e *syscall.FdSet, timeout *syscall.Timeval) c.Int