diff --git a/README.md b/README.md
index 9e2daa5..8af9ccb 100644
--- a/README.md
+++ b/README.md
@@ -615,9 +615,8 @@ double fibonaci(double x){
         return x;
     return fibonaci(x-1)+fibonaci(x-2);
 }
-// remember to use extern "C",
-// so you could search the symbol quickly
-extern "C" var fib(std::vector<var>& args,gc& ngc){
+// module functions' parameter list example
+var fib(var* args,usize size,gc* ngc){
     // the arguments are generated into a vm_vec: args
     // get values from the vector that must be used here
     var num=args[0];
@@ -627,10 +626,22 @@ extern "C" var fib(std::vector<var>& args,gc& ngc){
     if(num.type!=vm_num)
         return nas_err("extern_fib","\"num\" must be number");
     // ok, you must know that vm_num now is not managed by gc
-    // if want to return a gc object, use ngc.alloc(type)
+    // if want to return a gc object, use ngc->alloc(type)
     // usage of gc is the same as adding a native function
     return {vm_num,fibonaci(num.tonum())};
 }
+
+// must write this function, this will help nasal to
+// get the function pointer by name
+// the reason why using this way to get function pointer
+// is because `var` has constructors, which is not compatiable in C
+// so "extern "C" var fib" may get compilation warnings
+extern "C" mod get(const char* n){
+    string name=n;
+    if(name=="fib")
+        return fib;
+    return nullptr;
+}
 ```
 
 Next, compile this `fib.cpp` into dynamic lib.
diff --git a/doc/README_zh.md b/doc/README_zh.md
index c012c0b..a4c154a 100644
--- a/doc/README_zh.md
+++ b/doc/README_zh.md
@@ -590,19 +590,30 @@ double fibonaci(double x){
         return x;
     return fibonaci(x-1)+fibonaci(x-2);
 }
-// 记得用extern "C"
-// 这样找符号会更加快速便捷，不要在意编译时的warning
-extern "C" var fib(std::vector<var>& args,gc& ngc){
-    // 传参会被送到一个vm_vec类型中送过来，而不是上文中那种指针直接指向局部作用域
+
+// 模块函数的参数列表一律以这个为准
+var fib(var* args,usize size,gc* ngc){
+    // 传参会给予一个var指针，指向一个vm_vec的data()
     var num=args[0];
     // 如果你想让这个函数有更强的稳定性，那么一定要进行合法性检查
-    // builtin_err会输出错误信息并返回错误类型让虚拟机终止执行
+    // nas_err会输出错误信息并返回错误类型让虚拟机终止执行
     if(num.type!=vm_num)
         return nas_err("extern_fib","\"num\" must be number");
     // vm_num作为普通的数字类型，不是内存管理的对象，所以无需申请
-    // 如果需要返回内存管理的对象，请使用ngc.alloc(type)
+    // 如果需要返回内存管理的对象，请使用ngc->alloc(type)
     return {vm_num,fibonaci(num.tonum())};
 }
+
+// 必须实现这个函数, 这样nasal可以通过字符串名字获得函数指针
+// 之所以用这种方式来获取函数指针, 是因为`var`是有构造函数的
+// 有构造函数的类型作为返回值, 和C是不兼容的, 这导致
+// 类似 "extern "C" var fib" 的写法会得到编译错误
+extern "C" mod get(const char* n){
+    string name=n;
+    if(name=="fib")
+        return fib;
+    return nullptr;
+}
 ```
 
 接着我们把`fib.cpp`编译成动态库。
diff --git a/module/fib.cpp b/module/fib.cpp
index bac813d..cdac2ff 100644
--- a/module/fib.cpp
+++ b/module/fib.cpp
@@ -6,18 +6,20 @@ double fibonaci(double x){
         return x;
     return fibonaci(x-1)+fibonaci(x-2);
 }
-extern "C" var fib(std::vector<var>& args,gc& ngc){
+
+var fib(var* args,usize size,gc* ngc){
     std::cout<<"[mod] this is the first test module of nasal\n";
-    if(!args.size())
+    if(!size)
         return nas_err("fib","lack arguments");
     var num=args[0];
     if(num.type!=vm_num)
         return nas_err("extern_fib","\"num\" must be number");
     return {vm_num,fibonaci(num.tonum())};
 }
-extern "C" var quick_fib(std::vector<var>& args,gc& ngc){
+
+var quick_fib(var* args,usize size,gc* ngc){
     std::cout<<"[mod] this is the first test module of nasal\n";
-    if(!args.size())
+    if(!size)
         return nas_err("fib","lack arguments");
     var num=args[0];
     if(num.type!=vm_num)
@@ -31,4 +33,13 @@ extern "C" var quick_fib(std::vector<var>& args,gc& ngc){
         b=res;
     }
     return {vm_num,res};
+}
+
+extern "C" mod get(const char* n){
+    string name=n;
+    if(name=="fib")
+        return fib;
+    else if(name=="quick_fib")
+        return quick_fib;
+    return nullptr;
 }
\ No newline at end of file
diff --git a/module/keyboard.cpp b/module/keyboard.cpp
index dc70729..280a743 100644
--- a/module/keyboard.cpp
+++ b/module/keyboard.cpp
@@ -71,14 +71,25 @@ public:
 };
 
 noecho_input this_window;
-extern "C" var nas_getch(std::vector<var>& args,gc& ngc){
+var nas_getch(var* args,usize size,gc* ngc){
     return {vm_num,(double)this_window.noecho_getch()};
 }
-extern "C" var nas_kbhit(std::vector<var>& args,gc& ngc){
+var nas_kbhit(var* args,usize size,gc* ngc){
     return {vm_num,(double)this_window.noecho_kbhit()};
 }
-extern "C" var nas_noblock(std::vector<var>& args,gc& ngc){
+var nas_noblock(var* args,usize size,gc* ngc){
     if(this_window.noecho_kbhit())
         return {vm_num,(double)this_window.noecho_getch()};
     return nil;
+}
+
+extern "C" mod get(const char* n){
+    string name=n;
+    if(name=="nas_getch")
+        return nas_getch;
+    else if(name=="nas_kbhit")
+        return nas_kbhit;
+    else if(name=="nas_noblock")
+        return nas_noblock;
+    return nullptr;
 }
\ No newline at end of file
diff --git a/module/makefile b/module/makefile
index 5a74b84..9fb0d48 100644
--- a/module/makefile
+++ b/module/makefile
@@ -3,36 +3,41 @@
 STD=14
 
 libfib.so: fib.cpp
-	$(CXX) -std=c++$(STD) -c -O3 fib.cpp -fPIC -o fib.o
-	$(CXX) -shared -o libfib.so fib.o
-	rm fib.o
+	@ echo "[build] libfib.so"
+	@ $(CXX) -std=c++$(STD) -c -O3 fib.cpp -fPIC -o fib.o
+	@ $(CXX) -shared -o libfib.so fib.o
+	@ rm fib.o
 libfib.dll: fib.cpp
-	$(CXX) -std=c++$(STD) -c -O3 fib.cpp -fPIC -o fib.o
-	$(CXX) -shared -o libfib.dll fib.o
-	del fib.o
+	@ echo [build] libfib.dll
+	@ $(CXX) -std=c++$(STD) -c -O3 fib.cpp -fPIC -o fib.o
+	@ $(CXX) -shared -o libfib.dll fib.o
+	@ del fib.o
 
 libkey.so: keyboard.cpp
-	$(CXX) -std=c++$(STD) -c -O3 keyboard.cpp -fPIC -o keyboard.o
-	$(CXX) -shared -o libkey.so keyboard.o
-	rm keyboard.o
+	@ echo "[build] libkey.so"
+	@ $(CXX) -std=c++$(STD) -c -O3 keyboard.cpp -fPIC -o keyboard.o
+	@ $(CXX) -shared -o libkey.so keyboard.o
+	@ rm keyboard.o
 libkey.dll: keyboard.cpp
-	$(CXX) -std=c++$(STD) -c -O3 keyboard.cpp -fPIC -o keyboard.o -static
-	$(CXX) -shared -o libkey.dll keyboard.o -static
-	del keyboard.o
+	@ echo [build] libkey.dll
+	@ $(CXX) -std=c++$(STD) -c -O3 keyboard.cpp -fPIC -o keyboard.o -static
+	@ $(CXX) -shared -o libkey.dll keyboard.o -static
+	@ del keyboard.o
 
 libnasock.so: nasocket.cpp
-	$(CXX) -std=c++$(STD) -c -O3 nasocket.cpp -fPIC -o nasocket.o
-	$(CXX) -shared -o libnasock.so nasocket.o
-	rm nasocket.o
+	@ echo "[build] libnasock.so"
+	@ $(CXX) -std=c++$(STD) -c -O3 nasocket.cpp -fPIC -o nasocket.o
+	@ $(CXX) -shared -o libnasock.so nasocket.o
+	@ rm nasocket.o
 libnasock.dll: nasocket.cpp
-	$(CXX) -std=c++$(STD) -c -O3 nasocket.cpp -fPIC -o nasocket.o -lwsock32 -static
-	$(CXX) -shared -o libnasock.dll nasocket.o -lwsock32 -static
-	del nasocket.o
+	@ echo [build] libnasock.dll
+	@ $(CXX) -std=c++$(STD) -c -O3 nasocket.cpp -fPIC -o nasocket.o -lwsock32 -static
+	@ $(CXX) -shared -o libnasock.dll nasocket.o -lwsock32 -static
+	@ del nasocket.o
 
 clean:
 	-@ rm *.so *.dll *.dylib
-	@ echo "done"
 all: libfib.so libkey.so libnasock.so
-	@ echo "build done"
+	@ echo "[build] done"
 mingw-all: libfib.dll libkey.dll libnasock.dll
-	@ echo build done
\ No newline at end of file
+	@ echo [build] done
diff --git a/module/nasocket.cpp b/module/nasocket.cpp
index 5b12768..5c4a408 100644
--- a/module/nasocket.cpp
+++ b/module/nasocket.cpp
@@ -25,14 +25,14 @@ static WSAmanager win;
 #include <netinet/in.h>
 #endif
 
-extern "C" var nas_socket(std::vector<var>& args,gc& ngc){
+var nas_socket(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num || args[1].type!=vm_num || args[2].type!=vm_num)
         return nas_err("socket","\"af\", \"type\", \"protocol\" should be number");
     int sd=socket(args[0].num(),args[1].num(),args[2].num());
     return {vm_num,(double)sd};
 }
 
-extern "C" var nas_closesocket(std::vector<var>& args,gc& ngc){
+var nas_closesocket(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("closesocket","\"\" should be number");
 #ifdef _WIN32
@@ -42,7 +42,7 @@ extern "C" var nas_closesocket(std::vector<var>& args,gc& ngc){
 #endif
 }
 
-extern "C" var nas_shutdown(std::vector<var>& args,gc& ngc){
+var nas_shutdown(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("shutdown","\"sd\" must be a number");
     if(args[1].type!=vm_num)
@@ -50,7 +50,7 @@ extern "C" var nas_shutdown(std::vector<var>& args,gc& ngc){
     return {vm_num,(double)shutdown(args[0].num(),args[1].num())};
 }
 
-extern "C" var nas_bind(std::vector<var>& args,gc& ngc){
+var nas_bind(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("bind","\"sd\" muse be a number");
     if(args[1].type!=vm_str)
@@ -65,7 +65,7 @@ extern "C" var nas_bind(std::vector<var>& args,gc& ngc){
     return {vm_num,(double)bind(args[0].num(),(sockaddr*)&server,sizeof(server))};
 }
 
-extern "C" var nas_listen(std::vector<var>& args,gc& ngc){
+var nas_listen(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("listen","\"sd\" must be a number");
     if(args[1].type!=vm_num)
@@ -73,7 +73,7 @@ extern "C" var nas_listen(std::vector<var>& args,gc& ngc){
     return{vm_num,(double)listen(args[0].num(),args[1].num())};
 }
 
-extern "C" var nas_connect(std::vector<var>& args,gc& ngc){
+var nas_connect(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("connect","\"sd\" must be a number");
     if(args[1].type!=vm_str)
@@ -89,7 +89,7 @@ extern "C" var nas_connect(std::vector<var>& args,gc& ngc){
     return {vm_num,(double)connect(args[0].num(),(sockaddr*)&addr,sizeof(sockaddr_in))};
 }
 
-extern "C" var nas_accept(std::vector<var>& args,gc& ngc){
+var nas_accept(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("accept","\"sd\" must be a number");
     sockaddr_in client;
@@ -99,15 +99,15 @@ extern "C" var nas_accept(std::vector<var>& args,gc& ngc){
 #else
     int client_sd=accept(args[0].num(),(sockaddr*)&client,(socklen_t*)&socklen);
 #endif
-    var res=ngc.temp=ngc.alloc(vm_hash);
+    var res=ngc->temp=ngc->alloc(vm_hash);
     auto& hash=res.hash().elems;
     hash["sd"]={vm_num,(double)client_sd};
-    hash["ip"]=ngc.newstr(inet_ntoa(client.sin_addr));
-    ngc.temp=nil;
+    hash["ip"]=ngc->newstr(inet_ntoa(client.sin_addr));
+    ngc->temp=nil;
     return res;
 }
 
-extern "C" var nas_send(std::vector<var>& args,gc& ngc){
+var nas_send(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("send","\"sd\" must be a number");
     if(args[1].type!=vm_str)
@@ -117,7 +117,7 @@ extern "C" var nas_send(std::vector<var>& args,gc& ngc){
     return {vm_num,(double)send(args[0].num(),args[1].str().c_str(),args[1].str().length(),args[2].num())};
 }
 
-extern "C" var nas_sendto(std::vector<var>& args,gc& ngc){
+var nas_sendto(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("sendto","\"sd\" must be a number");
     if(args[1].type!=vm_str)
@@ -137,7 +137,7 @@ extern "C" var nas_sendto(std::vector<var>& args,gc& ngc){
     return {vm_num,(double)sendto(args[0].num(),args[3].str().c_str(),args[3].str().length(),args[4].num(),(sockaddr*)&addr,sizeof(sockaddr_in))};
 }
 
-extern "C" var nas_recv(std::vector<var>& args,gc& ngc){
+var nas_recv(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("recv","\"sd\" must be a number");
     if(args[1].type!=vm_num)
@@ -146,17 +146,17 @@ extern "C" var nas_recv(std::vector<var>& args,gc& ngc){
         return nas_err("recv","\"len\" out of range");
     if(args[2].type!=vm_num)
         return nas_err("recv","\"flags\" muse be a number");
-    var res=ngc.temp=ngc.alloc(vm_hash);
+    var res=ngc->temp=ngc->alloc(vm_hash);
     auto& hash=res.hash().elems;
     char* buf=new char[(int)args[1].num()];
     hash["size"]={vm_num,(double)recv(args[0].num(),buf,args[1].num(),args[2].num())};
-    hash["str"]=ngc.newstr(buf);
+    hash["str"]=ngc->newstr(buf);
     delete[] buf;
-    ngc.temp=nil;
+    ngc->temp=nil;
     return res;
 }
 
-extern "C" var nas_recvfrom(std::vector<var>& args,gc& ngc){
+var nas_recvfrom(var* args,usize size,gc* ngc){
     if(args[0].type!=vm_num)
         return nas_err("recvfrom","\"sd\" must be a number");
     if(args[1].type!=vm_num)
@@ -167,7 +167,7 @@ extern "C" var nas_recvfrom(std::vector<var>& args,gc& ngc){
         return nas_err("recvfrom","\"flags\" muse be a number");
     sockaddr_in addr;
     int socklen=sizeof(sockaddr_in);
-    var res=ngc.temp=ngc.alloc(vm_hash);
+    var res=ngc->temp=ngc->alloc(vm_hash);
     auto& hash=res.hash().elems;
     char* buf=new char[(int)args[1].num()+1];
 #ifdef _WIN32
@@ -176,13 +176,42 @@ extern "C" var nas_recvfrom(std::vector<var>& args,gc& ngc){
     hash["size"]={vm_num,(double)recvfrom(args[0].num(),buf,args[1].num(),args[2].num(),(sockaddr*)&addr,(socklen_t*)&socklen)};
 #endif
     buf[(int)hash["size"].num()]=0;
-    hash["str"]=ngc.newstr(buf);
+    hash["str"]=ngc->newstr(buf);
     delete[] buf;
-    hash["fromip"]=ngc.newstr(inet_ntoa(addr.sin_addr));
-    ngc.temp=nil;
+    hash["fromip"]=ngc->newstr(inet_ntoa(addr.sin_addr));
+    ngc->temp=nil;
     return res;
 }
 
-extern "C" var nas_errno(std::vector<var>& args,gc& ngc){
-    return ngc.newstr(strerror(errno));
+var nas_errno(var* args,usize size,gc* ngc){
+    return ngc->newstr(strerror(errno));
+}
+
+extern "C" mod get(const char* n){
+    string name=n;
+    if(name=="nas_socket")
+        return nas_socket;
+    else if(name=="nas_closesocket")
+        return nas_closesocket;
+    else if(name=="nas_shutdown")
+        return nas_shutdown;
+    else if(name=="nas_bind")
+        return nas_bind;
+    else if(name=="nas_listen")
+        return nas_listen;
+    else if(name=="nas_connect")
+        return nas_connect;
+    else if(name=="nas_accept")
+        return nas_accept;
+    else if(name=="nas_send")
+        return nas_send;
+    else if(name=="nas_sendto")
+        return nas_sendto;
+    else if(name=="nas_recv")
+        return nas_recv;
+    else if(name=="nas_recvfrom")
+        return nas_recvfrom;
+    else if(name=="nas_errno")
+        return nas_errno;
+    return nullptr;
 }
\ No newline at end of file
diff --git a/nasal_builtin.h b/nasal_builtin.h
index 8bd4b43..5828da7 100644
--- a/nasal_builtin.h
+++ b/nasal_builtin.h
@@ -130,7 +130,7 @@ var builtin_split(var* local,gc& ngc)
 
     // avoid being sweeped
     var res=ngc.temp=ngc.alloc(vm_vec);
-    std::vector<var>& vec=res.vec().elems;
+    auto& vec=res.vec().elems;
 
     if(!deli.length())
     {
@@ -850,7 +850,7 @@ var builtin_getenv(var* local,gc& ngc)
     char* res=getenv(envvar.str().c_str());
     return res?ngc.newstr(res):nil;
 }
-void obj_dylib_dtor(void* ptr)
+void dylib_dtor(void* ptr)
 {
 #ifdef _WIN32
     FreeLibrary((HMODULE)ptr);
@@ -869,7 +869,7 @@ var builtin_dlopen(var* local,gc& ngc)
         return nas_err("dlopen","malloc failed");
     memset(str,0,sizeof(wchar_t)*dlname.str().size()+1);
     mbstowcs(str,dlname.str().c_str(),dlname.str().size()+1);
-    void* ptr=LoadLibraryW(str);
+    void* ptr=LoadLibraryA(dlname.str().c_str());
     delete []str;
 #else
     void* ptr=dlopen(dlname.str().c_str(),RTLD_LOCAL|RTLD_LAZY);
@@ -877,7 +877,7 @@ var builtin_dlopen(var* local,gc& ngc)
     if(!ptr)
         return nas_err("dlopen","cannot open dynamic lib <"+dlname.str()+">");
     var ret=ngc.alloc(vm_obj);
-    ret.obj().set(nas_obj::dylib,ptr,obj_dylib_dtor);
+    ret.obj().set(nas_obj::dylib,ptr,dylib_dtor);
     return ret;
 }
 var builtin_dlsym(var* local,gc& ngc)
@@ -888,15 +888,20 @@ var builtin_dlsym(var* local,gc& ngc)
         return nas_err("dlsym","\"lib\" is not a valid dynamic lib");
     if(sym.type!=vm_str)
         return nas_err("dlsym","\"sym\" must be string");
+    // "get" function
 #ifdef _WIN32
-    void* func=(void*)GetProcAddress((HMODULE)lib.obj().ptr,sym.str().c_str());
+    void* func=(void*)GetProcAddress((HMODULE)lib.obj().ptr,"get");
 #else
-    void* func=dlsym(lib.obj().ptr,sym.str().c_str());
+    void* func=dlsym(lib.obj().ptr,"get");
 #endif
     if(!func)
-        return nas_err("dlsym","cannot find symbol \""+sym.str()+"\"");
+        return nas_err("dlsym","cannot find get function");
+    // get function pointer by name
+    void* ptr=(void*)((getptr)func)(sym.str().c_str());
+    if(!ptr)
+        return nas_err("dlsym","cannot find function <"+sym.str()+">");
     var ret=ngc.alloc(vm_obj);
-    ret.obj().set(nas_obj::faddr,func);
+    ret.obj().set(nas_obj::faddr,ptr);
     return ret;
 }
 var builtin_dlclose(var* local,gc& ngc)
@@ -918,9 +923,8 @@ var builtin_dlcall(var* local,gc& ngc)
     var args=local[2];
     if(!fp.objchk(nas_obj::faddr))
         return nas_err("dlcall","\"funcptr\" is not a valid function pointer");
-    typedef var (*externs)(std::vector<var>&,gc&);
-    externs func=(externs)fp.obj().ptr;
-    return func(args.vec().elems,ngc);
+    auto& vec=args.vec().elems;
+    return ((mod)fp.obj().ptr)(vec.data(),vec.size(),&ngc);
 }
 
 var builtin_platform(var* local,gc& ngc)
diff --git a/nasal_gc.h b/nasal_gc.h
index 3fa21d6..8caa574 100644
--- a/nasal_gc.h
+++ b/nasal_gc.h
@@ -460,16 +460,18 @@ struct gc
     } mctx;
     
     /* runtime context */
-    u32&  pc;    // program counter
-    var*& localr;// local scope register
-    var*& memr;  // used for mem_call
-    var&  funcr; // function register
-    var&  upvalr;// upvalue register
-    var*& canary;// avoid stackoverflow
-    var*& top;   // stack top
-    var*  stack; // stack pointer
-    nas_co* cort;// running coroutine
-    var   temp;  // temporary place used in builtin/module functions
+    u32&  pc;     // program counter
+    var*& localr; // local scope register
+    var*& memr;   // used for mem_call
+    var&  funcr;  // function register
+    var&  upvalr; // upvalue register
+    var*& canary; // avoid stackoverflow
+    var*& top;    // stack top
+    var*  stack;  // stack pointer
+    nas_co* cort; // running coroutine
+
+    /* native function used */
+    var temp; // temporary place used in builtin/module functions
 
     /* constants and memory pool */
     std::vector<var> strs;        // reserved address for const vm_str
@@ -720,4 +722,8 @@ var nas_err(const string& err_f,const string& info)
     std::cerr<<"[vm] "<<err_f<<": "<<info<<"\n";
     return {vm_none};
 }
+
+typedef var (*mod)(var*,usize,gc*); // module function type
+typedef mod (*getptr)(const char*); // module function "get" type
+
 #endif
\ No newline at end of file
diff --git a/nasal_vm.h b/nasal_vm.h
index ecbeee0..03038d1 100644
--- a/nasal_vm.h
+++ b/nasal_vm.h
@@ -602,7 +602,7 @@ inline void vm::o_findex()
 }
 inline void vm::o_feach()
 {
-    std::vector<var>& ref=top[-1].vec().elems;
+    auto& ref=top[-1].vec().elems;
     if((usize)(++top[0].cnt())>=ref.size())
     {
         pc=imm[pc]-1;
@@ -800,8 +800,8 @@ inline void vm::o_slc2()
 {
     var val2=(top--)[0];
     var val1=(top--)[0];
-    std::vector<var>& ref=top[-1].vec().elems;
-    std::vector<var>& aim=top[0].vec().elems;
+    auto& ref=top[-1].vec().elems;
+    auto& aim=top[0].vec().elems;
 
     u8 type1=val1.type,type2=val2.type;
     i32 num1=val1.tonum();
diff --git a/test/httptest.nas b/test/httptest.nas
index 97fd283..347bf23 100644
--- a/test/httptest.nas
+++ b/test/httptest.nas
@@ -5,7 +5,10 @@ var http=func(){
     return {
         establish:func(ip,port){
             sd=socket.socket(socket.AF_INET,socket.SOCK_STREAM,socket.IPPROTO_IP);
-            socket.bind(sd,ip,port);
+            if(socket.bind(sd,ip,port)<0){
+                println("failed to bind socket "~sd~" at IP: "~ip~" port: "~port~".");
+                return;
+            }
             socket.listen(sd,1);
             println("[",os.time(),"] start server at [",ip,":",port,"]");
         },
@@ -40,7 +43,6 @@ var http=func(){
 }();
 http.establish("127.0.0.1",8080);
 
-
 var highlight_style="
 <style>
     body{
diff --git a/test/occupation.nas b/test/occupation.nas
index e2fb228..a3686e5 100644
--- a/test/occupation.nas
+++ b/test/occupation.nas
@@ -16,14 +16,20 @@ var cpu_stat=func(){
     };
     return cpu;
 }
+
 var cpu_occupation=func(){
-    var cpu0=cpu_stat();
-    unix.sleep(0.5);
-    var cpu1=cpu_stat();
-    var t0=cpu0.user+cpu0.nice+cpu0.system+cpu0.idle+cpu0.iowait+cpu0.irq+cpu0.softirq;
-    var t1=cpu1.user+cpu1.nice+cpu1.system+cpu1.idle+cpu1.iowait+cpu1.irq+cpu1.softirq;
-    var interval=cpu1.idle-cpu0.idle;
-    return t0==t1?0:(1-interval/(t1-t0))*100;
+    while(1){
+        var cpu0=cpu_stat();
+        for(var i=0;i<5;i+=1){
+            unix.sleep(0.1);
+            coroutine.yield(nil);
+        }
+        var cpu1=cpu_stat();
+        var t0=cpu0.user+cpu0.nice+cpu0.system+cpu0.idle+cpu0.iowait+cpu0.irq+cpu0.softirq;
+        var t1=cpu1.user+cpu1.nice+cpu1.system+cpu1.idle+cpu1.iowait+cpu1.irq+cpu1.softirq;
+        var interval=cpu1.idle-cpu0.idle;
+        coroutine.yield(t0==t1?0:(1-interval/(t1-t0))*100);
+    }
 }
 
 var mem_occupation=func(){
@@ -36,20 +42,24 @@ var mem_occupation=func(){
     }
     return mem_res;
 }
+
 func(){
     if(os.platform()=="windows"){
         println("haven't supported yet.");
         return;
     }
+    var co=coroutine.create(cpu_occupation);
+    var bar=process_bar.high_resolution_bar(30);
     print("\ec");
     while(1){
         var mem=mem_occupation();
         var mem_occ=(mem.MemTotal-mem.MemFree)/mem.MemTotal*100;
-        var cpu_occ=cpu_occupation();
-        var key=libkey.nonblock();
-        var bar=process_bar.high_resolution_bar(25);
-        if(key!=nil and chr(key)=="q")
-            break;
+        var cpu_occ=nil;
+        while((cpu_occ=coroutine.resume(co)[0])==nil){
+            var key=libkey.nonblock();
+            if(key!=nil and chr(key)=="q")
+                return;
+        }
         println("\e[1;1H\e[1m Memory total(GB)    : \e[0m\e[36m",mem.MemTotal/1024/1024,"\e[0m");
         println("\e[2;1H\e[1m Memory free(GB)     : \e[0m\e[36m",mem.MemFree/1024/1024,"\e[0m");
         println("\e[3;1H\e[1m Memory occupation(%): \e[0m",mem_occ>60?"\e[91m":"\e[32m",bar.bar(mem_occ/100)~" ",mem_occ,"\e[0m         ");