C++11 predefined macro

Question

Are there any predefined macros for C++ in order the code could identify the standard?

e.g. Currently most compilers puts "array" into "tr1" folder but for C++11 it would be part of STL. So currently

#include <tr1/array> 

but c++11

#include <array> 

What is the predefined macros for 03 standard and 11 standard in order I can use #ifdef to identify?

Also, I suppose there are macros for C90 and C99?

Thanksx

Answer 1

From Stroustrup's C++11 FAQ

In C++11 the macro __cplusplus will be set to a value that differs from (is greater than) the current 199711L.

You can likely test it's value to determine if it's c++0x or not then.

Answer 2

Nitpick...

Your particular issue does not depend on your compiler, it depends on the Standard Library implementation.

Since you are free to pick a different Standard Library that the one provided by your compiler (for example, trying out libc++ or stlport), no amount of compiler specific information will help you here.

Your best bet is therefore to create a specific header file yourself, in which you will choose either one or the other (depending on a build option).

// array.hpp #ifdef STD_HAS_TR1_ARRAY_HEADER #include <tr1/array> #else #include <array> #endif 

You then document the compiler option:

Passing -DSTD_HAS_TR1_ARRAY_HEADER will mean that std::tr1::array is defined in <tr1/array> instead of the default <array>.

And you're done.