长期由系统架构定义，还是IEEE标准？

Working on getting some communication of longs between computers and chips. Was running into some issues and thought it might be because the definition of longs between different system architectures (We're talking between 32-bit and 64-bit machines). Does anyone know if longs are an IEEE standard (like floats and doubles), or if they vary based on system architecture? (like ints)Working on getting some communication of longs