Know Your Types
Most portability issues that generate warnings are because we are not careful about our types. Standard library and arrays are indexed with
size_t. Standard container sizes are reported in
size_t. If you get the handling of
size_t wrong, you can create subtle lurking 64-bit issues that arise only after you start to overflow the indexing of 32-bit integers. char vs unsigned char.
Use The Standard Library
C++17 added a new
filesystem library which provides portable filesystem access across all supporting compilers
C++11's threading capabilities should be utilized over
Most of the other concerns in this document ultimately come back to portability issues. Avoid statics is particularly of note.