Modern C++ Basics - Programming in Mutiple Files

inline namespace#

namespace {
namespace impl_v1 {
}
inline namespace impl_v2 {
}
}

inline#

• With the rapid development of compiler optimization, compilers today basically don’t care whether you use inline or not.
• Since C++17, inline variables are introduced.
  • We’ve said that global variables should also split declaration and definition;
  • So inline variables can be directly put into headers, and only needs to be ODR in each TU.
• However, inline functions / variables may cause double symbols in shared libraries.