C / C++ / MFC

Mark Salsbery wrote:

sockets only understand bytes.

To send a struct you send it as a stream of bytes.

To get a pointer to the struct use the "address of" operator (&)
You'll need to cast this to a char* for some socket operations.

For the length of the struct (in bytes), use the sizeof operator.

When you receive the number of bytes equal to the sizeof the struct, you can cast a pointer to
those bytes into a struct pointer or just receive the bytes directly into a struct object.

<br />
typedef struct DATASTRUCT {<br />
<br />
   char* sParam1;<br />
};<br />

<br />
struct DATASTRUCT ServerResponse;<br />
ServerResponse.sParam1 = "Welcome to the Server";<br />
send(sckConnection, (char*)&ServerResponse, sizeof(ServerResponse), 0);<br />

<br />
char* inBuffer = (char*)malloc(2048);<br />
int nRecv = recv(sckClient, inBuffer, 2048, 0);<br />
<br />
if ( nRecv == sizeof(DATASTRUCT*) )<br />
{<br />
	DATASTRUCT IncomingData; <br />
	IncomingData = (DATASTRUCT*)inBuffer;<br />
        MessageBox(hWnd, IncomingData->sParam1, "incoming data", MB_OK);<br />
}<br />

deerhunter89 wrote:

typedef struct DATASTRUCT {

char* sParam1;
};

enum { DATA_BUFFER_SIZE = 1024 };<br />
typedef struct DATASTRUCT {<br />
  char param1[DATA_BUFFER_SIZE];<br />
};

class CServerSocket<br />
{<br />
  enum { DATA_BUFFER_SIZE = 1024 };<br />
  struct DATASTRUCT {<br />
    char param1[DATA_BUFFER_SIZE];<br />
    char param2[DATA_BUFFER_SIZE];<br />
  };<br />
};<br />
<br />
const char* SERVER_STR1 = "Welcome to the Server";<br />
const char* SERVER_STR2 = "The weather is fine today";<br />
<br />
CServerSocket::SendResponse(SOCKET sckConnection)<br />
{<br />
DATASTRUCT serverResponse<br />
strncpy(serverResponse.param1, SERVER_STR1, DATA_BUFFER_SIZE);<br />
strncpy(serverResponse.param2, SERVER_STR2, DATA_BUFFER_SIZE);<br />
send(sckConnection, (const char*)&serverResponse, sizeof(serverResponse), 0);<br />
}

deerhunter89 wrote:

char* inBuffer = (char*)malloc(2048);
int nRecv = recv(sckClient, inBuffer, 2048, 0);

if ( nRecv == sizeof(DATASTRUCT*) )
{
DATASTRUCT IncomingData;
IncomingData = (DATASTRUCT*)inBuffer;
MessageBox(hWnd, IncomingData->sParam1, "incoming data", MB_OK);
}

hero1995 wrote:

db.Execute(strSQL);