Thank you for your response, please allow me to explain the problem a bit clearer: The -MM option in gcc does the following (from the man page on my Linux system): "instead of outputting the result of preprocessing, output a rule suitable for make describing the dependencies of the main source file. The preprocessor outputs one make rule containing the object file name for that source file, a colon, and the names of all the included files, including those coming from -include or -imacros command line options." In projects using the gcc compiler, this is a preferred way to take care of the dependencies. However, this does not work anymore with the new boost version, because, unless the macro BOOST_PARAMETER_MAX_ARITY is defined to no less than 7, the preprocessor aborts, whilst figuring out the dependencies, due to the following lines in signals2/signal_type.hpp: #if !defined(BOOST_PARAMETER_MAX_ARITY) #define BOOST_PARAMETER_MAX_ARITY 7 #else #if BOOST_PARAMETER_MAX_ARITY < 7 #error This header requires BOOST_PARAMETER_MAX_ARITY to be defined as 7 or greater prior to including Boost.Parameter headers #endif // BOOST_PARAMETER_MAX_ARITY < 7 #endif // !defined(BOOST_PARAMETER_MAX_ARITY) This means that the gcc native way of figuring out dependencies, is broken. I believe this cannot be intended. Please let me know if the problem is still not understood, or if you have a different view on this matter. Kind regards, Ytsen. 2011/9/13 Dave Abrahams :

on Mon Sep 05 2011, Ytsen de Boer wrote:

...

  Hi,

  To take care of dependencies in my project using boost, I used to invoke gcc with the option -MM.

What does -MM do?

...

However, since using boost 1.47, this does not work anymore. The precompiler aborts with the message:

/usr/local/include/boost-1_47/boost/signals2/signal_type.hpp:29:2: error: #error This header requires BOOST_PARAMETER_MAX_ARITY to be defined as 7 or greater prior to including Boost.Parameter headers

  Because the macro BOOST_PARAMETER_MAX_ARITY plays no role whatsover in this invocation of gcc, I think that boost should solve their internal problem with the "arity" in some other way.

I don't know what you mean.  It defaults to 5, but signals2 apparently needs support for 7 arguments.

...

  In the mean time I define the macro in my make rules to generate the dependencies, but there it is obviously misplaced (any tips or tricks are welcome here).

I don't understand your problem, sorry.

-- Dave Abrahams BoostPro Computing http://www.boostpro.com

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Thank you for your answer. I believe we are not on the same page. Obviously, when I define the max arity to a value of 7 or more, the preprocessor will finish properly. But the point I am trying to make is more subtle, namely, that the generation of the project dependencies has not a thing to do with the boost max arity. Therefore, the definition of that macro would be terribly misplaced in the make rule for the dependencies, which has only to do with the dependent files and nothing with the numeric values of macros. At least, that is how it should be in my opinion. I don't know what the boost max arity means or what its for, but it seems to me that it is a run time variable. As such, it should be handled by the code and not by preprocessor directives, surely not with this side-effect. I hope this can be acknowledged. Kind regards, Ytsen. 2011/9/15 Ivan Le Lann :

----- "Ytsen de Boer" a écrit :

...

Thank you for your response, please allow me to explain the problem a bit clearer:

(removed -MM explanation)

I believe this has nothing to do with -MM. Does your code compile without dependency generation ?

Obviously Boost.Signals2 needs this macro to be at least 7. You probably include another boost library before Signals2 that default it to less than 7.

See: http://boost.2283326.n4.nabble.com/Accumulators-Signals2-Compilation-error-w... I think you should define this macro (to 7 or more) in your compiler command.

Regards, Ivan _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users