no. of arguments in boost::bind

Question

How many maximum arguments can we pass to boost::bind()

score 12 · Accepted Answer · answered Feb 10 '11 at 10:23

12

by default it's 9.

http://www.boost.org/doc/libs/1_45_0/libs/bind/bind.html#NumberOfArguments

answered Feb 10 '11 at 10:23

KitsuneYMG

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And if you are calling functions with more than 9 arguments then you need to rethink your design! – GrahamS Feb 10 '11 at 11:00
@GrahamS I think boost.lambda bind takes up to 9 as well. Boost.Spirit.Phoenix, the library I use for functional programming, has default 10 w/a macro to define the upper limit. – KitsuneYMG Feb 10 '11 at 11:06
I wrote an IOC system that required templates per argument used to construct objects. I think it ended up going as high as 12. Was probably too many – CashCow Feb 10 '11 at 11:50
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@GrahamS : sometimes you just have to consume headers from some commecrial external libraries where discussing the design with the vendor isn't an option. – Ichthyo Jul 03 '13 at 21:30

score 3 · Answer 2 · answered Jul 03 '13 at 21:29

Even if you can't switch to C++11, you should consider switching from boost::function to the TR1 functions, which was a preview for C++11

Basically, what started out as boost::function became part of the C++ standard library, which nowadays is defined with variadic templates. In a nutshell this means that there is no hard limit anymore (but you might need to define additional placeholder variables if you need something beyond _19 )

To switch from boost::function to std::tr1 do the following

find all occurences of #include <boost/function> and #include <boost/bind> and replace them by:

 #include <tr1/functional>
 using std::tr1::function;
 using std::tr1::bind;
 using std::tr1::placeholders::_1;
 using std::tr1::placeholders::_2;
...

This should work as a drop-in replacement. If you happen to switch to C++11 later, just throw out the "tr1" part.

no. of arguments in boost::bind

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