Read File Into Buffer And Write That Buffer To Another File?

[Rehorav]

Hey everyone, I'm trying to play around with a few things. Now I'm playing around with reading binary files (and now I'm playing with writing). Now heres something weird, I'm reading a file into a buffer, but that buffer wrote write properly to another file.

 
 
unsigned char *Buffer, *Buffer2;
DWORD FileSize, BytesRead;
HANDLE hFile = CreateFile ( "app.exe", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL );
SelectedFileSize = GetFileSize ( hFile, NULL );
if ( hFile == NULL )
{
MessageBox ( NULL, "Invalid filename...exiting!", "Error", NULL );
//return 0;
}
if ( ( FileSize = GetFileSize ( hFile, NULL ) ) < 0 ) 
{
MessageBox ( NULL, "Error Retrieving File Size", "Error", NULL );
CloseHandle ( hFile );
exit ( 0 );
}
Buffer2 = Buffer = ( unsigned char* ) malloc ( FileSize );
if ( !ReadFile ( hFile, Buffer, FileSize, &BytesRead, NULL ) )
{
MessageBox ( NULL, "Error Reading File", "Error", NULL );
CloseHandle ( hFile );
free ( Buffer );
exit ( 0 );
}

As you can see in the above code, I'm just reading it into the buffer.

Now, when I try something along the lines of:

 
HANDLE MyFile = CreateFile ( "filename.ext", GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, 0, NULL );
DWORD Bytes;
WriteFile(MyFile, (unsigned char*)Buffer, sizeof ( Buffer ), &Bytes, NULL);
CloseHandle(MyFile);

or:

 
FILE * pFile = fopen("filename.ext", "r+b");
fwrite(Buffer, sizeof ( Buffer ), sizeof ( Buffer ), pFile);
fclose(pFile);

The only thing it writes is "MZ ÿÿ ". Which isn't even close to the full size of the file (the file is about 3.5 KB total).

I know I'm doing something wrong, but I can't figure what. Would you all mind giving me a hand?

[Igor Vartanov]

WriteFile(MyFile, (unsigned char*)Buffer, sizeof ( Buffer ), &Bytes, NULL);

Buffer is a pointer. Size of pointer is 4, but not what you expected. You have to use BytesRead instead.