C++ allows you to define functions with unnamed arguments. For example:
void tester(int) { }; main(int, char **) { tester(1); };
Though you cannot use unnamed arguments elsewhere in a program, dbx encodes unnamed arguments in a form that allows you to evaluate them. The form is:
_ARG_%n_
where dbx assigns an integer to %n.
To obtain an assigned argument name from dbx, issue the whatis command with the function name as its target:
(dbx) whatis tester void tester(int _ARG_0_); (dbx) whatis main int main(int _ARG_1_, char **_ARG_2_);
To evaluate (or display) an unnamed function argument,
(dbx) print _ARG_1_ _ARG_1_ = 4