What is the native endianness of my platform?

[kitfox]

I have a third party library that says it returns an array of data in the native endianness of my platform. Trouble is, how do I know what the native endianness of my platform is? Is there some sort of compile time flag I can check to test this?

[mpergand]

     bool isBigEndian()
             {
             static const int i = 1;
             static bool endian= ( (*(char*)&i) == 0 );
             return endian;
             }

https://developer.ibm.com/articles/au-endianc/

There are some Qt macros also:

Q_BIG_ENDIAN
This macro represents a value you can compare to the macro
Q_BYTE_ORDER to determine the endian-ness of your system. 
In a big-endian system, the most significant byte is stored at the lowest address. 
The other bytes follow in decreasing order of significance.

  #if Q_BYTE_ORDER == Q_BIG_ENDIAN
  ...
  #endif

See also Q_BYTE_ORDER and Q_LITTLE_ENDIAN.
Q_BYTE_ORDER

[hskoglund]

Hi, also there's a Qt class QSysInfo that has a ByteOrder enum, query it like this:

#include "qsysinfo.h"
qDebug() << QSysInfo::ByteOrder;

this returns 0 on big endian platforms and 1 on little endians