Project – Enable C++11 Compiling

By default, GCC C++ compiles for the corrected C++98 standard (C++03) with GNU extensions (there is no option for compiling for the uncorrected original C++98 standard).  There are two options for compiling C++11, one for the standard and one with GNU extensions.  The option for the standard C++11 will be used and was added to the CMake build file.

Though not necessary, I decided that it was a reasonable idea to validate that C++11 compiling was enabled and that C++11 was supported while generating the make file.  This meant adding a try_compile command to the CMake build file for a simple C++11 program.  If compiling of the simple program fails, an error is reported and CMake aborts.

The initial simple C++11 program tests two C++11 features.  As more C++11 features are used in the project, this simple program will be expanded to test those features also.  The two initial features tested are the new universal initializer syntax and the new null pointer.  Click Continue... for details of these two features.

I discovered something about CMake syntax, namely else and endif statements no longer require repeating the expression in the if statement (as of CMake 2.6.0).  The expression may now be left empty.  Repeating the expression can sometimes be misleading, for example:

if (NOT ${SOMETHING})
    ... <not something processing here> ...
else  (NOT ${SOMETHING})
    ... <something procession here> ...
endif (NOT ${SOMETHING})

Which makes it seem like the else part is for handling the "not something" condition.  Leaving the expression blank, as in else() and endif(), is much less confusing.  The rest of the if-else-endif statements in the CMake file will be updated to this style at some point.  (This syntax was already used for handling issues with Windows.)

There was also a statement in the CMake build file that obtained the GCC version for checking, but statements that were checking the version have been since removed, so this statement was also removed.  Work is now taking place on a new cpp11 branch.

[branch cpp11 commit 18ed38e9af]