title: How can I detect if I'm compiling for a 64bits architecture in C++
body: <p>In a C++ function I need the compiler to choose a different block if it is compiling for a 64 bit architecture.</p>
  
  <p>I know a way to do it for MSVC++ and g++, so I'll post it as an answer. However I would like to know if there is a better way (more elegant that would work for all compilers/all 64 bits architectures). If there is not a better way, what other predefined macros should I look for in order to be compatible with other compiler/architectures?</p>