brad@bwilab3.UUCP (Bradley Ward) (12/08/90)
When I write a callback routine such as those used by X windows, many times I don't need to use the "client_data" argument. But the C++ compiler issues a "unused argument" warning. I hate to have warnings generated, so I have been doing stuff like putting the statement "client_data = client_data;" in the callback simply to eliminate this compiler warning. (I hope the optimizer is smart enought to take this out!). Any ideas on how to handle this more elegantly ? Bradley Ward Phone: 404-396-4292 BRADLEY WARD, INC. FAX: 404-396-6509 5901-A Peachtree Dunwoody Road, N.E. Suite 415 Atlanta, Georgia 30328 ...!uunet!gatech!galbp!bwilab3!brad
roman@hri.com (Roman Budzianowski) (12/10/90)
Define the callback as:
void acallback(Widget w, caddr_t, caddr_t closure)
{}
i.e. omit the variable you are not using.thomas@hpugrca.HP.COM (Thomas Buenermann) (12/12/90)
> the C++ compiler issues a "unused argument" warning. You might try something like void startCB (Widget,caddr_t client_data) { printf("Button %s action.\n",client_data); } which does not generate warnings on our C++. I also like to get rid of warnings this way... Regards, Thomas
jgro@lia (Jeremy Grodberg) (12/13/90)
In article <133@bwilab3.UUCP> brad@bwilab3.UUCP (Bradley Ward) writes: >When I write a callback routine such as those used by X windows, >many times I don't need to use the "client_data" argument. But >the C++ compiler issues a "unused argument" warning. > >Any ideas on how to handle this... elegantly ? Leave the names of the unused varaibles out of the declaration of the callback routine. In other words, if the callback is int callback(int x, int y, int z) and you don't use y, then just declare it as int callback(int x, int, int z) and then you won't get any warnings about the unused y. -- Jeremy Grodberg "I don't feel witty today. Don't bug me." jgro@lia.com
mat@mole-end.UUCP (Mark A Terribile) (12/14/90)
> When I write a callback routine such as those used by X windows, > many times I don't need to use the "client_data" argument. But > the C++ compiler issues a "unused argument" warning. I hate to > have warnings generated, so I have been doing stuff like putting > the statement "client_data = client_data;" in the callback simply > to eliminate this compiler warning.... It seems to me we've seen this three times in six weeks. comp.lang.c has a Frequently Asked Qestions list that is posted periodically. Is it time for comp.lang.c++ to get a FAQ of its own? If I could promise the time to do it, I'd volunteer. For the present, I can't. But if anyone would like to, here's one reader who would be grateful. Oh, the correct answer to the question is ReadTheFructatingManual! The useful answer is `Omit the argument name in the argument list, but leave the type (as though you were casting).' -- (This man's opinions are his own.) From mole-end Mark Terribile
ahodgson@athena.mit.edu (Antony Hodgson) (12/18/90)
Just place the argsused pragma in front of the offending function. Tony Hodgson ahodgson@hstbme.mit.edu