C++ main: Portable code

[Wolfos]

Portable code is compilable on multiple platforms without changing anything in the source.
In this tutorial I will explain the way I do this.

The precompiler carries some constants, from this you are able to find out which platform the compiler is running on.
Because it's such little code I will just completely post it here:

//detect Mac OS-X
#if (defined(__MACH__))
   //code for Mac platform, __Apple__ can also be used but that can result in problems
#elif defined (__linux__)
  //code for Linux platform
#elif defined (_WIN32)
  //code for Windows platform (also for 64 bit)
#else
  //unknown platform
#endif

Or, if the same code is being used for multiple Operating Systems:

#if (defined(__MACH__))|| defined (__linux__)
  //code for Mac AND Linux
#elif defined (_WIN32)
  //code for Windows
#else
  //unknown platform
#endif

[Wolfos]

Forgot the link to C++:main

[Dragonslayerk]

I must be brain-dead, but how does this work?

For some reason, it seems like placing that in your code magically allows it to
run on mac, windows, and Linux.

if(above_statement_is_false)
tell_me( what you need to do);

[Momo-the-Monkey]

At 2/15/11 06:18 PM, Dragonslayerk wrote: For some reason, it seems like placing that in your code magically allows it to
run on mac, windows, and Linux.

That code lets you write code for different machines/OSs without having separate programs. That way, you can send the ONE file to any computer, and it will work.

These tags only tell you what machine/OS you're running on and don't magically grant you a free-pass on your own code when it comes to compatibility. It just makes machine/os detection easier.

[Dragonslayerk]

At 2/15/11 09:26 PM, Momo-the-Monkey wrote:
That code lets you write code for different machines/OSs without having separate programs. That way, you can send the ONE file to any computer, and it will work.

These tags only tell you what machine/OS you're running on and don't magically grant you a free-pass on your own code when it comes to compatibility. It just makes machine/os detection easier.

yeah, I thought so, I'm just dead today.
I'm having trouble comprehending the world today. Sorry.

[Redshift]

At 2/15/11 09:26 PM, Momo-the-Monkey wrote:

At 2/15/11 06:18 PM, Dragonslayerk wrote: For some reason, it seems like placing that in your code magically allows it to
run on mac, windows, and Linux.

That code lets you write code for different machines/OSs without having separate programs. That way, you can send the ONE file to any computer, and it will work.

These tags only tell you what machine/OS you're running on and don't magically grant you a free-pass on your own code when it comes to compatibility. It just makes machine/os detection easier.

Um, no? It's only for compiling. You'd need a runtime environment for real portability (eg, Java). But the C preprocessor only governs compilation time. You still have to compile separate binaries. It's useful because you don't actually have to change the source code when you want to compile for a certain OS.

[Momo-the-Monkey]

Ah yes, I did lose myself, didn't I? You are correct, I apologize. There is only one file for compilation, which still means you don't have to mess with different files for different OSs, just the binaries.

You are correct, I apologize.

[Wolfos]

At 2/15/11 06:18 PM, Dragonslayerk wrote: I must be brain-dead, but how does this work?

For some reason, it seems like placing that in your code magically allows it to
run on mac, windows, and Linux.

No, I will explain again.

#if (defined(__MACH__))

Checks for Mac OS-X, any code between that and the next #elif, #elseif or #endif will only be compiled on a computer running Mac OS-X.