To inject x64 DLL's into x64 processes, you should use x64 pointers. But as you are using handles instead of pointers, the compiler can take care of its length instead of you. So compiling this ...

Allocates memory in the target process. Writes the DLL path into the process memory. Creates a remote thread to execute the DLL using LoadLibraryA. Supports both x86 and x64 architectures. Click the ...