How portable is C++ as a programming language (in terms of different operating systems andhardware)?
C++ is a fairly new language that until recently did not specify anystandard library components. The draft ANSI/ISO specifies theprecise definition of the language and its libraries. So once all vendors become 100 percent standard-compliant, and you write code using onlystandard language features and library calls, your code will be fully portable..
In reality, almost all compilers are different in one way or another. Some have included the more recent features like exceptions templates, name spaces and newer keywords,. while others have not.
Vendors tend to include OS-specific libraries so people can developapplications for that platform, so any program using these special libraries will not port very easily.
The strategy in the last few years has been to use third-party librarieslike RogueWave or Booch components, and avoid the more advanced featuresof the language like exception handling.