0

I got this simple code:

#include "stdio.h"
#include "stdlib.h"
#include "windows.h"

int main(int argc, CHAR* argv[])
{
    HANDLE hFile = NULL;
    HANDLE hMapFile = NULL;
    LPBYTE fileView;

    hFile = CreateFile(argv[1],GENERIC_READ,FILE_SHARE_READ,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
    if(hFile == INVALID_HANDLE_VALUE)
    {
        printf("CreateFile function failed\n");
        goto clean;
    }

***** hMapFile = (LPBYTE)CreateFileMapping(hFile,NULL,PAGE_READONLY,0,256,NULL);*****
if(hMapFile == NULL)
{
printf("CreateFileMapping function failed\n");
goto clean;
}
fileView = MapViewOfFile(hMapFile,FILE_MAP_READ,0,0,0);
if(fileView == NULL)
{
printf("CreateFileMapping function failed\n");
goto clean;
}

clean:
    CloseHandle(hFile);
    CloseHandle(hMapFile);
    system("PAUSE");
    return 0;
}

And for some reason in the line that is underlined it says that I cannot convert LPVOID to LPBYTE

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Last Post by BobS0327
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You are trying to convert the return value of CreateFileMapping() to the wrong type. It already returns the correct type, so no typecasting is needed.

0

So how can I use this after I do this function?
I just have to cast the void pointer every time I want to use it as a byte type?

0
  1. Remove (LPBYTE) from CreateFileMapping(...)
  2. I'm guessing that you're wanting to do something with the mapped file, in which case you'd have:

    fileView = (LPBYTE)MapViewOfFile(hMapFile, FILE_MAP_READ, 0, 0, 0);

Edited by nullptr

0

I just have to cast the void pointer every time I want to use it as a byte type?

hMapFile is NOT a byte ptr -- its HANDLE which is already the type returned by CreateFileMaping(). And where do you see a void pointer??? I don't see that sort of object in the code you posed.

Edited by Ancient Dragon

0

Your primary problem is not with the following statement although it should not be typecasted as LPBYTE

> ***** hMapFile = (LPBYTE)CreateFileMapping(hFile,NULL,PAGE_READONLY,0,256,NULL);*****

The problem is caused by the following statement:

> fileView = MapViewOfFile(hMapFile,FILE_MAP_READ,0,0,0);

MapViewOfFile returns a LPVOID data type. fileView is a LPBYTE data type.

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