Macro definition for message mapping

Question

Hi all; Formerly I asked a question and got a fair response. But I am stucked with below macro definitions.

The below definitions generates a Message Map function like it is in MFC Message Map. But the code below does not compile.

Whole statements starting with this-> are problematic ones except the one in MSG_HANDLER this->meth(msg); dont know why..

Hence what can be done to correct this issue?

I use VS 2008.

#define MSG_UNPACK(var, id, msg) x##id *var = (x##id *)(msg);

#define BEGIN_MSG_MAP                          \
   protected:                                  \
   virtual void dispatchToMsgMap(xMessage *msg)\
   {                                           \
     if (msg->msg.message == WM_NULL)          \
     {                                         \
       return;                                 \
     }

#define MSG_HANDLER(meth, wm_msg)              \
     else if (msg->msg.message == wm_msg)      \
     {                                         \
       this->meth(msg);                        \
       return;                                 \
     }

#define END_MSG_MAP(base)                      \
     else if (msg->msg.message == WM_COMMAND)  \
     {                                         \                       
       this->dispatchToCmdMap(msg);            \                       
       return;                                 \                       
     }                                         \                       
     else if (msg->msg.message == WM_NOTIFY)   \                       
     {                                         \                       
       this->dispatchToNotifyMap(msg);         \                       
       return;                                 \                       
     }                                         \                       
                                               \                       
     base::dispatchToMsgMap(msg);              \                       
   };

#define BEGIN_CMD_MAP                          \
   virtual void dispatchToCmdMap(xMessage *msg)\
   {                                           \                              
     MSG_UNPACK(Cmd, WM_COMMAND, msg);         \                              
                                               \                              
     if (Cmd->ItemID == 0)                     \                              
     {                                         \                              
        /* not allowed */                      \                              
     }                                                                        

#define CMD_HANDLER(meth, cmd_id)              \
     else if (Cmd->ItemID == cmd_id)           \
     {                                         \                                
       this->meth(Cmd->ItemID);                \                                
     }                                                                          

#define END_CMD_MAP(base)                      \
     else                                      \                              
     {                                         \                              
       base::dispatchToCmdMap(msg);        \                              
     }                                         \                              
   };

Here, for example this->dispatchToCmdMap(msg); \ is 41st line.

1>d:\devel\coding\vs2008\test2\test2\messagemapper.h(41) : error C2059: syntax error : 'this' 1>d:\devel\coding\vs2008\test2\test2\messagemapper.h(41) : error C2017: illegal escape sequence 1>d:\devel\coding\vs2008\test2\test2\messagemapper.h(42) : error C2059: syntax error : 'return' 1>d:\devel\coding\vs2008\test2\test2\messagemapper.h(42) : error C2017: illegal escape sequence 1>d:\devel\coding\vs2008\test2\test2\messagemapper.h(43) : error C2059: syntax error : '}' 1>d:\devel\coding\vs2008\test2\test2\messagemapper.h(43) : error C2143: syntax error : missing ';' before '}' 1>d:\devel\coding\vs2008\test2\test2\messagemapper.h(43) : error C2059: syntax error : '}'

Answer 1

First, check that you haven't got whitespace after the slashes at the the end of the lines.

If that doesn't help then you should look at the pre-processed output to see what is actually being compiled (and post that here if you need to).

Answer 2

The "illegal escape sequence" part tells me that you have traling whitespace after your \. Therefore the next lines are not part of the macro.

Answer 3

Try to remove spaces after "\". This symbol should be the last in the line.