Major Update:

- FunctionCore
  - Replace Channel->Ready with Channel->State (off/waiting/ready)
  - Add Function reference to Handle
- SelectableBare/Core:
  - Implement async address resolve with event handling
    - Create ResolveHandler() signal handler (friend) function
  - Change Create/Remove/DestroyHandle() methods to virtual methods
    - Move socket specific code to SelectableCore
  - Rename ChangeState() to virtual HandleState()
  - Move ClearHandle() from SelectableBare -> SelectableCore
  - Implement new/delete from THandle
  - Set max TCP SYN count on connect

SelectableCore.h

@@ -10,6 +10,8 @@
 
 // Standard C/C++ Libraries
 #include <ctype.h>
+#include <signal.h>
+#include <netdb.h>
 
 // redA Libraries
 #include "FunctionCore.h"
@@ -44,13 +46,14 @@ const char ConnectStateName[][15] = { "None", "OpenRequest", "WaitingToOpen", "O
 // Previews
 typedef struct SSelectHandle    TSelectHandle;
 typedef struct SHandle          THandle;
+typedef struct SResolveReq      TResolveReq;
 
 class CSelect;
 class CSelectableBare;
 class CSelectableCore;
 
 // Callback function for handle events
-typedef void (*FHandleCallback)( CSelectableBare * Function, THandle * Handle, EConnectState State );
+typedef void (*FHandleCallback)( CSelectableBare * Function, THandle * Handle, EConnectState OldState );
 
 //---------------------------------------------------------------------------
 
@@ -68,7 +71,6 @@ struct SSelectHandle {
     // List
     TSelectHandle       * Next      = NULL;
 };
-
 //---------------------------------------------------------------------------
 
 // List or Handles for Selectable Function Object
@@ -76,6 +78,7 @@ struct SHandle {
     // Description
     char            * Name      = NULL;
     EConnectType    Type        = ctNone;
+    CSelectableBare * Function  = NULL;
 
     // State
     int             FD          = -1;
@@ -103,7 +106,10 @@ struct SHandle {
     struct addrinfo * AddressInfo   = NULL;     // Current selected IP Address
     bool            AddressFailed   = false;    // Indicate failure to connect to address
     short           Queue           = 2;        // Max waiting connections
+
     long            ResolveDelay    = 0;        // Delay before resolving hostname via DNS
+    TResolveReq     * ResolveReq    = NULL;     // DNS resolve request
+    bool            Resolving       = false;    // Busy resolving address
 
     // Serial Port config
     bool        SerialConfig    = false;
@@ -132,6 +138,16 @@ struct SHandle {
     THandle     * Parent        = NULL;
     THandle     * Next          = NULL;
 };
+//---------------------------------------------------------------------------
+
+struct SResolveReq {
+    THandle             * Handle        = NULL;
+    gaicb               * Request       = NULL;
+};
+//---------------------------------------------------------------------------
+
+// Resolving
+void ResolveHandler( int Signal, siginfo_t * SignalInfo, void * Context );
 
 //---------------------------------------------------------------------------
 
@@ -192,9 +208,9 @@ protected:
     CSelect     * Selector      = NULL;
 
     // Managing File Handles
-    bool RemoveHandle( THandle * Handle );
-    bool DestroyHandle( THandle * Handle );
-    bool ChangeState( THandle * Handle, EConnectState State );
+    virtual bool RemoveHandle( THandle * Handle );
+    virtual bool DestroyHandle( THandle * Handle );
+    virtual bool HandleState( THandle * Handle, EConnectState State );
 
     // Get Parameters
     inline int  GetFD( const char * HandleName ) {
@@ -241,7 +257,7 @@ public:
     }
 
     // General port parameters
-    THandle *   CreateHandle( const char * HandleName, bool CreateChannel );
+    virtual THandle *     CreateHandle( const char * HandleName, bool CreateChannel );
     virtual CDataMember * GetHandleAddress( THandle * Handle, const char * HandleRef );
 
     bool    SetCallback( THandle * Handle, EConnectState pState, FHandleCallback pCallback );
@@ -249,9 +265,6 @@ public:
     bool    SetInBuffer( THandle * Handle, int InBufSize, int InTimeout, const char * InMarker, int InMarkerLen );
     bool    SetOutBuffer( THandle * Handle, int OutBufSize );
 
-    // Specific port parameters
-    bool    ClearHandle( THandle * Handle );
-
     // FD Operations
     virtual int  Open( THandle * Handle, bool DelayResolve = false ) = 0;
     virtual bool Close( THandle * Handle, bool QuickReopen );
@@ -291,6 +304,8 @@ public:
 class CSelectableCore : public CSelectableBare
 {
 protected:
+    struct  sigaction   ResolveAct;
+
     // Port Operations
     THandle *   OpenSerialPort( THandle * Handle );
     bool        WriteSerialConfig( THandle * Handle );
@@ -306,6 +321,11 @@ protected:
 
     // Socket Operations
     bool    ResolveAddress( THandle * Handle, bool DelayResolve );
+    bool    HandleResolve( THandle * Handle );
+    bool    DestroyResolveReq( THandle * Handle, bool DestroyResult );
+
+    // Managing File Handles
+    virtual bool DestroyHandle( THandle * Handle );
 
     THandle *   OpenUDPserverSocket( THandle * Handle, bool DelayResolve );
     THandle *   OpenUDPremoteSocket( THandle * Handle, char * RemoteAddr, char * RemotePort );
@@ -330,6 +350,8 @@ public:
     virtual bool  Init( CDataMember * FunctionConfig );
 
     // Specific port parameters
+    bool    ClearHandle( THandle * Handle );
+
     bool    SetSerialHandle( THandle * Handle, const char * FileName );
     bool    SetSerialHandleConfig( THandle * Handle, int Baudrate, short DataBits, short Parity, short StopBits, short FlowCtrl, int DataWait );
     bool    SetLinePrinterHandle( THandle * Handle, const char * FileName );
@@ -346,6 +368,8 @@ public:
     // Function Interface
     virtual int  OutputHandle( THandle * Handle, const char * Data, int Len );
     virtual bool Process();
+
+    friend void ResolveHandler( int Signal, siginfo_t * SignalInfo, void * Context );
 };
 
 //---------------------------------------------------------------------------