C++ is standardized by the international standards body ISO, so one might expect it to be similar across different operating systems. Ironically, it is the only popular programming language that doesn't provide a consistent cross platform experience.

Some examples of incompatability

• The global namespace is littered differently across platforms. Can you use an innocent looking name like Point?
  • max often breaks std::max in Visual Studio, while std::max<int> or (std::max) work fine
• Which standard library functions are available depend on your compiler version. Use std::gcd? Your code won't work on Visual Studio 2015
  • Some things are available under different names, like std::array vs std::tr1::array
  • While not unique to C++, it does have it much worse because due to a lack of package management, developers are encouraged to use the standard library as much as possible
• Xcode limits usage of C++ features if you wish to support older macOS versions
• Standard C constants like M_PI are missing in Visual Studio unless you #define _USE_MATH_DEFINES before #include <math.h>
  • As a consequence, changing the order of includes often breaks compilation!
• Want to use __has_include to conditionally compile parts of your library? It's only available in C++17 so check __cplusplus to see if you can use it. But in VS it doesn't really tell you the language version so be sure to check _MSC_VER too..
• Equivalent attributes have different syntaxes - __attribute__((aligned(32))) vs __declspec(align(32))
• Run-time crashes in Windows upon using dynamic_cast with virtual inheritence while they work fine on macOS

How did we get there

The original sin - compatibility for your soul

C++ owes its success to being a superset of C, which made the transition easy for users of the popular systems language of the time.

There are many choices to make when designing a language, and the choices should work together if we want to reach a cohesive and sensible design. By inheriting all of C's choices, C++ handicapped its ability of doing this.

C++ has went so far that even its own name is a reference to a C++ anti-pattern.

Embrace, extend, and extinguish

Microsoft of the 1990s and early 2000s famously used the EEE strategy in the browser wars.

They have clearly also used it in the PL/OS wars:

• Make Visual Studio the best IDE for C++, gain users, and gradually break compatability with other implementations
• Code developed in the IDE will not work in other OSs, less software for those means users will keep preferring Windows
• Profit!

Complicated standards are bug prone

We all know that programming is difficult. And standartisation is a form of programming. Relatively simple standards like the shapes and sizes of screws can be implemented successfully, but implementing a complicated standard like C++ without errors is unfeasable.

What's next

C++ is currently the king in some industries (games, audio) because no other popular language addresses their needs. Sadly, I don't see this changing in the near future.

Perhaps one day Rust, Pony, D, Zig, Jai, or something that I haven't heard about will overtake C++'s throne. Let's hope, anything but this!

Misc

• r/cpp discussion
• Removed mistake from the list after getting corrections from mjklaim and encyclopedist
• Image source: Le Gregman Show, translated by Monjipour