portability

Take a look at this simple Java program: import java.lang.*; class A { static boolean done; public static void main(String args[]) { done = false; new Thread() { public void run() { try { Thread.sleep(1000); // dummy work load } catch (Exception e) { done = true; } done = true; } }.start(); while (!done); System.out.println("bye"); } } On one machine, it prints "bye" and exits right away, while on another machine, it doesn't print anything and sits there forever. Why? This is because your boolean is not volatile , therefore Thread s are allowed to cache copies of it and never update them. I

This question already has an answer here: Who determines the ordering of characters 6 answers I see nothing wrong with the following program, and this being non-portable is really confusing to me. According to the book by Mike Banahan (GBdirect C Book, Section 2.4.2) , the following program is non-portable. Reason given is: Another example, perhaps. This will either print out the whole lower case alphabet, if your implementation has its characters stored consecutively, or something even more interesting if they aren't. C doesn't make many guarantees about the ordering of characters in internal

I have some Django middleware code that connects to a database. I want to turn the middleware into a reusable application ("app") so I can package it for distribution into many other projects, without needing to copy-and-paste. I don't understand where a reusable application is supposed to configure itself. Since it's intended for redistribution I don't have the ability to write the central settings.py myself. Looking at the Django documentation I see there's settings.configure but it appears to replace the entire configuration, instead of letting me "splice" a new database into DATABASES.

Is there a well-known, portable, good library for C++ process management? I found a promising library called Boost.Process , but it's only a candidate for inclusion in the Boost library. Has anyone use this? Does anyone know why it isn't a part of Boost? How much management do you need? Just fork/exec? IPC? Resource management? Security contexts and process isolation ? I haven't used the Boost.Process library. However, I do know that getting included in Boost is a rather difficult affair. Boost recently accepted a futures library that had already been approved as part of the standard. However,

How portable is code that uses #pragma optimize ? Do most compilers support it and how complete is the support for this #pragma ? #pragma is the sanctioned and portable way for compilers to add non-sanctioned and non-portable language extensions * . Basically, you never know for sure, and at least one major C++ compiler (g++) does not support this pragma as is. * : From the C++ standard (N3242): 16.6 Pragma directive [cpp.pragma] A preprocessing directive of the form # pragma pp-tokens opt new-line causes the implementation to behave in an implementation-defined manner. The behavior might

I'm using __get_cpuid() to get info on the x86 and x86_64 processors my programs run on. With GCC on Linux and Mac OS, it seems to compile and run OK without include any header, but how portable is that? Would it work with other compilers? Should I include a header for that? It has two leading underscores. Any leading underscore at all is a big hint that the variable or function is not portable. 来源： https://stackoverflow.com/questions/8407001/how-portable-is-get-cpuid

I'm interested in writing some cross-platform code using Mono, with a view to targeting mobile iOS and Android runtimes. I've perused the Mono and MonoTouch sites, but don't see anything that specifically advises on methods not to use, or Mono hooks which should be avoided. However, that seems a little too good to be true. What limitations should I be aware of going into this project, to ensure maximum portability of the code? API wise you get a very similar base class libraries (BCL) when using MonoTouch or Mono for Android (M4A) since both share the same mobile profile (which was originally