Hello all. I would like to know if there's a boost library for solving this problem, or if not, if it would be of general interest one. Suppose you have a function in an external library that you want to use, and it have this prototype: ... /* mad_library.h */ /* external library function prototype */ double qk15( double(*f)(double), double a, double b); (this example mimics QUADPACK, a great and wonderful library for numerical integration) If you want to have a (good) chance of using qk15 with a reentrant function, then the correct prototype would be, at least ... double qk15( double(*f)(double, void*), double a, double b, void* params); ... which is something that for example gsl (http://www.gnu.org/software/gsl/ ) does. But that's not the case and modifying qk15 is out of the question. So, the "solution" library I'm asking for should be a C++ header library that would, for example, bring this interface to the user: ... #include <mad_library.h> // Hypothetical library #include <boost/enable_reentrant.hpp> // client functor supplied by the user, to be used in some // way with 'qk15' struct any_functor{ ... double operator()(double x) ... }; ... // an instance of the functor any_functor cpp_f; ... // first parameter is the legacy function, following parameter // types are deduced from the prototype of qk15 (if // possible), being each one of the same original type that // qk15 requires but changing raw function pointers by generic // functors (automatic type replacement or user-guided). boost::enable_reentrant(qk15, cpp_f, a, b); // As a postcondition to this call, function qk15 should // be called once with a function pointer to something that // ensures that operator() on 'any_functor' instance get's // called with the corresponding 'this'. If I'm missing something terrible obvious please signal it to me. I think enable_reentrant can be implemented in at least one (almost) portable way, using a stack in thread local storage. Boost.Thread already give access to such feature in a satisfactory way. __________________________________________________________________ Servicio de Correos del Grupo de Redes. UCLV - Universidad 2008 del 11 al 15 de febrero del 2008. Palacio de Convenciones. La Habana. Cuba. http: //www.universidad2008.cu - II Taller internacional -Virtualización en la Educación Superior-, del 11 al 15 de febrero de 2008 Palacio de Convenciones. La Habana, Cuba. http://virtual-es.uclv.edu.cu