It says something about not defined. A guess is that it is a syntax thing, perhaps #10 needs to be specified (it is assuming 10 is the address or function name?)
Possible extensions - is an integer better treated as an address or as a line number? (fhpd) break &10 -- breakpoint at address 10 (instead of gdb's *10????) (fhpd) break 10 -- breakpoint at line 10 -> integer (fhpd) break 10+1 -- breakpoint at line 11 -> integer (fhpd) break 0x10 -- breakpoint at line 16 -> integer (fhpd) break 1.0 The intent of the following is pretty clear: (fhpd) break &function -- break at function entry point (fhpd) break function -- break at function (possibly skipping prologue?????) (fhpd) break &(function + 10) -- breakpoint at &function + 10 (fhpd) break function + 10 -- ditto -> at "pointer address" hint is: (fhpd) print (function + 10) (*)() 0x12234 (fhpd) break aclass::asubclass::overloadedfunction<int>(int)