C / C++ / MFC

pix_programmer wrote:

How to do this?

TCHAR szMsg[]=TEXT("Message from first process.");
CopyMemory((PVOID)pBuf, szMsg, (_tcslen(szMsg) * sizeof(TCHAR)));  

hMapFile = OpenFileMapping(
                   FILE_MAP_ALL_ACCESS,   // read/write access
                   FALSE,                 // do not inherit the name
                   szName);   

 pBuf = (LPTSTR) MapViewOfFile(hMapFile, // handle to map object
               FILE_MAP_ALL_ACCESS,  // read/write permission
               0,                    
               0,                    
               BUF_SIZE);   

 MessageBox(NULL, pBuf, TEXT("Process2"), MB_OK);

#include <stdio.h>
#include <stdlib.h>

#define buffSize 2048
char buffer[buffSize];

void initBuffer()
{
    memset((PVOID)buffer, 0, sizeof(char) * buffSize);
}

// returns number of messages in buffer
// -1 if failed
int addMsg(char *msg)
{
    long msgCount, curMsgIndex, curMsgLen;
    char *newStrPos;

    memcpy((PVOID)&msgCount, buffer, sizeof(long));

    newStrPos = (char*) (long)&buffer + sizeof(long);

    for (curMsgIndex=0; curMsgIndex<msgCount; curMsgIndex++)
    {
        curMsgLen = strlen(newStrPos);
        newStrPos += curMsgLen + 1;
    }

    // don't forget to check that this message won't overflow the buffer!!!
    // I didn't bother for this simple example
    //if ( ((newStrPos-buffer)+strlen(msg)+1) < buffSize)
    {
        printf("adding message\n");
        strcpy(newStrPos, msg);
        msgCount++;
        memcpy((PVOID)buffer, &msgCount, sizeof(long));
    }
    //else
    //    printf("unable to add message\n");

}

void printMessages()
{
    long msgCount, curMsgNum;
    char *curMsg;

    memcpy(&msgCount, buffer, sizeof(long));
    curMsg = (char*)(long)&buffer + sizeof(long);
    for (curMsgNum=0; curMsgNum<msgCount;curMsgNum++)
    {
            printf("%s\n", curMsg);
            curMsg += strlen(curMsg) + 1;
    }
}

int main()
{
    initBuffer();
    addMsg("This is msg 1");
    addMsg("This is msg 2");
    printMessages();
    return 0;
}