Writing DWORD to end of file on Windows-CodePudding

I am trying to figure out how to write a integer value to the end of my file. The value is size.

DWORD size = 12314432;
BOOL ret = WriteFile(hFile, size, sizeof(DWORD), NULL, NULL);

However WriteFile() requires that parameter 3 be of type LPCVOID so I am not sure how I would give it the DWORD instead.

I have tried..

unsigned char b[sizeof(DWORD)] = {0};
sprintf(b, "%d", size);
WriteFile(hFile, b, sizeof(DWORD), NULL, NULL);

However this just puts the hex value of each digit. So if size=1234 then it would write "31 32 33 44" to end of the file.

I would like the end of the file to just get the number in 4 bytes.

CodePudding user response：

You provide the address of the DWORD like this:

DWORD size = 12314432;
BOOL ret = WriteFile(hFile, &size, sizeof size, NULL, NULL);

Use the ampersand to get the address of the DWORD variable.
Express your intend for the size, you want to write all of size, so say so.

CodePudding user response：

You can pass (void*)&size. You do need something which has an address, like size. You can't pass an expression there. (void*) &(5*7 3) won't work.