[balls187]

> Could somebody point me to a technical explanation of why it's sometimes non trivial to just compile your app against x86-64 and call it a day?

"In 32-bit programs, pointers and data types such as integers generally have the same length. This is not necessarily true on 64-bit machines. Mixing data types in programming languages such as C and its descendants such as C++ and Objective-C may thus work on 32-bit implementations but not on 64-bit implementations." [1]

It's non-trivial to ensure every developer writes portable code multiplied by the varying degree of skills for developers.

In a language like C++, assuming the size of an integer is 4-bytes, or that the size of all pointer types are the same, can introduce hard to track down bugs, which may result in 64-bit versions of apps to be unstable.

[1]: https://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_m...