diff --git a/nexgb/xgbgen/context.go b/nexgb/xgbgen/context.go
index d433531..35dd37e 100644
--- a/nexgb/xgbgen/context.go
+++ b/nexgb/xgbgen/context.go
@@ -5,6 +5,7 @@ import (
 	"encoding/xml"
 	"fmt"
 	"log"
+	"strings"
 	"time"
 )
 
@@ -70,6 +71,43 @@ func (c *Context) Morph(xmlBytes []byte) {
 		c.Putln("")
 	}
 
+	// If this is an extension, create a function to initialize the extension
+	// before it can be used.
+	if c.protocol.isExt() {
+		name := strings.Title(c.protocol.Name) + "Init"
+		xname := c.protocol.ExtXName
+
+		c.Putln("// %s must be called before using the %s extension.",
+			name, xname)
+		c.Putln("func (c *Conn) %s() error {", name)
+		c.Putln("reply, err := c.QueryExtension(%d, \"%s\").Reply()",
+			len(xname), xname)
+		c.Putln("switch {")
+		c.Putln("case err != nil:")
+		c.Putln("return err")
+		c.Putln("case !reply.Present:")
+		c.Putln("return newError(\"No extension named %s could be found on " +
+			"on the server.\")", xname)
+		c.Putln("}")
+		c.Putln("")
+		c.Putln("c.extLock.Lock()")
+		c.Putln("c.extensions[\"%s\"] = reply.MajorOpcode", xname)
+		c.Putln("for evNum, fun := range newExtEventFuncs[\"%s\"] {", xname)
+		c.Putln("newEventFuncs[int(reply.FirstEvent) + evNum] = fun")
+		c.Putln("}")
+		c.Putln("c.extLock.Unlock()")
+		c.Putln("")
+		c.Putln("return nil")
+		c.Putln("}")
+		c.Putln("")
+
+		// Make sure newExtEventFuncs["EXT_NAME"] map is initialized.
+		c.Putln("func init() {")
+		c.Putln("newExtEventFuncs[\"%s\"] = make(map[int]newEventFun)", xname)
+		c.Putln("}")
+		c.Putln("")
+	}
+
 	// Now write Go source code
 	for _, typ := range c.protocol.Types {
 		typ.Define(c)
diff --git a/nexgb/xgbgen/go_error.go b/nexgb/xgbgen/go_error.go
index 152db8b..0222289 100644
--- a/nexgb/xgbgen/go_error.go
+++ b/nexgb/xgbgen/go_error.go
@@ -64,7 +64,7 @@ func (e *Error) ImplementsError(c *Context) {
 	c.Putln("}")
 	c.Putln("")
 	c.Putln("func (err %s) BadId() Id {", e.ErrType())
-	if c.protocol.Name == "xproto" {
+	if !c.protocol.isExt() {
 		c.Putln("return Id(err.BadValue)")
 	} else {
 		c.Putln("return 0")
diff --git a/nexgb/xgbgen/go_event.go b/nexgb/xgbgen/go_event.go
index 9bc6dfe..ce54e19 100644
--- a/nexgb/xgbgen/go_event.go
+++ b/nexgb/xgbgen/go_event.go
@@ -47,7 +47,12 @@ func (e *Event) Define(c *Context) {
 
 	// Let's the XGB event loop read this event.
 	c.Putln("func init() {")
-	c.Putln("newEventFuncs[%d] = New%s", e.Number, e.EvType())
+	if c.protocol.isExt() {
+		c.Putln("newExtEventFuncs[\"%s\"][%d] = New%s",
+			c.protocol.ExtXName, e.Number, e.EvType())
+	} else {
+		c.Putln("newEventFuncs[%d] = New%s", e.Number, e.EvType())
+	}
 	c.Putln("}")
 	c.Putln("")
 }
@@ -130,7 +135,12 @@ func (e *EventCopy) Define(c *Context) {
 
 	// Let's the XGB event loop read this event.
 	c.Putln("func init() {")
-	c.Putln("newEventFuncs[%d] = New%s", e.Number, e.EvType())
+	if c.protocol.isExt() {
+		c.Putln("newExtEventFuncs[\"%s\"][%d] = New%s",
+			c.protocol.ExtXName, e.Number, e.EvType())
+	} else {
+		c.Putln("newEventFuncs[%d] = New%s", e.Number, e.EvType())
+	}
 	c.Putln("}")
 	c.Putln("")
 }
diff --git a/nexgb/xgbgen/go_request_reply.go b/nexgb/xgbgen/go_request_reply.go
index e64e2a2..451667f 100644
--- a/nexgb/xgbgen/go_request_reply.go
+++ b/nexgb/xgbgen/go_request_reply.go
@@ -118,7 +118,7 @@ func (r *Request) WriteRequest(c *Context) {
 	c.Putln("b := 0")
 	c.Putln("buf := make([]byte, size)")
 	c.Putln("")
-	if strings.ToLower(c.protocol.Name) != "xproto" {
+	if c.protocol.isExt() {
 		c.Putln("buf[b] = c.extensions[\"%s\"]",
 			strings.ToUpper(c.protocol.ExtXName))
 		c.Putln("b += 1")
@@ -128,17 +128,17 @@ func (r *Request) WriteRequest(c *Context) {
 	c.Putln("b += 1")
 	c.Putln("")
 	if len(r.Fields) == 0 {
-		if strings.ToLower(c.protocol.Name) == "xproto" {
+		if !c.protocol.isExt() {
 			c.Putln("b += 1 // padding")
 		}
 		writeSize()
-	} else if strings.ToLower(c.protocol.Name) != "xproto" {
+	} else if c.protocol.isExt() {
 		writeSize()
 	}
 	for i, field := range r.Fields {
 		field.Write(c, "")
 		c.Putln("")
-		if i == 0 && strings.ToLower(c.protocol.Name) == "xproto" {
+		if i == 0 && !c.protocol.isExt() {
 			writeSize()
 		}
 	}
diff --git a/nexgb/xgbgen/protocol.go b/nexgb/xgbgen/protocol.go
index 505b400..e01bc17 100644
--- a/nexgb/xgbgen/protocol.go
+++ b/nexgb/xgbgen/protocol.go
@@ -36,6 +36,6 @@ func (p *Protocol) Initialize() {
 // isExt returns true if this protocol is an extension.
 // i.e., it's name isn't "xproto".
 func (p *Protocol) isExt() bool {
-	return strings.ToLower(p.Name) == "xproto"
+	return strings.ToLower(p.Name) != "xproto"
 }
 
diff --git a/nexgb/xgbgen/request_reply.go b/nexgb/xgbgen/request_reply.go
index 7cd2859..c7a4cf8 100644
--- a/nexgb/xgbgen/request_reply.go
+++ b/nexgb/xgbgen/request_reply.go
@@ -22,7 +22,7 @@ type Request struct {
 // It also initializes the reply if one exists, and all fields in this request.
 func (r *Request) Initialize(p *Protocol) {
 	r.srcName = SrcName(p, r.xmlName)
-	if p.Name != "xproto" {
+	if p.isExt() {
 		r.srcName = strings.Title(strings.ToLower(p.Name)) + r.srcName
 	}
 
@@ -93,7 +93,7 @@ func (r *Request) Size(c *Context) Size {
 	// request. In an extension request, this byte is always occupied
 	// by the opcode of the request (while the first byte is always occupied
 	// by the opcode of the extension).
-	if c.protocol.Name == "xproto" {
+	if !c.protocol.isExt() {
 		size = size.Add(newFixedSize(3))
 	} else {
 		size = size.Add(newFixedSize(4))
diff --git a/nexgb/xgbgen/translation.go b/nexgb/xgbgen/translation.go
index 90cd0f3..592c152 100644
--- a/nexgb/xgbgen/translation.go
+++ b/nexgb/xgbgen/translation.go
@@ -410,7 +410,7 @@ func TypeSrcName(p *Protocol, typ Type) string {
 	// Since there is no namespace, we need to look for a namespace
 	// in the current context.
 	niceType := splitAndTitle(t)
-	if p.Name != "xproto" {
+	if p.isExt() {
 		for _, typ2 := range p.Types {
 			if t == typ2.XmlName() {
 				return strings.Title(p.Name) + niceType