-XBT_PRIVATE boost::intrusive_ptr<simgrid::kernel::activity::ExecImpl>
-SIMIX_execution_start(const char* name, double flops_amount, double priority, double bound, sg_host_t host);
-XBT_PRIVATE boost::intrusive_ptr<simgrid::kernel::activity::ExecImpl>
-SIMIX_execution_parallel_start(const char* name, int host_nb, sg_host_t* host_list, double* flops_amount,
+XBT_PRIVATE simgrid::kernel::activity::ExecImplPtr SIMIX_execution_start(std::string name, std::string category,
+ double flops_amount, double priority,
+ double bound, sg_host_t host);
+XBT_PRIVATE simgrid::kernel::activity::ExecImplPtr
+SIMIX_execution_parallel_start(std::string name, int host_nb, sg_host_t* host_list, double* flops_amount,