Messages in this thread | | | Date | Fri, 8 May 2009 13:47:45 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 1/2] tracing/events: clean up for ftrace_set_clr_event() |
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On Fri, May 08, 2009 at 07:35:22AM -0400, Steven Rostedt wrote: > > On Fri, 8 May 2009, Frederic Weisbecker wrote: > > > > > > -static int ftrace_set_clr_event(char *buf, int set) > > > +/* > > > + * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events. > > > + */ > > > +static int __ftrace_set_clr_event(const char *match, const char *sub, > > > + const char *event, int set) > > > { > > > struct ftrace_event_call *call; > > > + int ret; > > > + > > > + mutex_lock(&event_mutex); > > > + list_for_each_entry(call, &ftrace_events, list) { > > > + > > > + if (!call->name || !call->regfunc) > > > + continue; > > > + > > > + if (match && > > > + strcmp(match, call->name) != 0 && > > > + strcmp(match, call->system) != 0) > > > + continue; > > > + > > > + if (sub && strcmp(sub, call->system) != 0) > > > + continue; > > > + > > > + if (event && strcmp(event, call->name) != 0) > > > + continue; > > > > > > Neat: You can simply use !strcmp(...) > > Hehe, no he can't. It would be "strcmp(...)" for the true case. This is > exactly why I prefer to use "strcmp(...) != 0" over "!strcmp(...)". > Because, like you, I've confused "!strcmp(...)" too many times as "not a > match" when it in fact means "is a match". > > I've made this mistake enough that I've given up on using just "strcmp" or > "!strcmp". "strcmp() != 0" and "strcmp() == 0" show what you want much > better. >
You're right. It provides a good disambiguation. The C philosophy has this 0 == SUCCESS convention which doesn't match the human brain logic that expect 0 is a false and 1 is a true....
I guess that's because "!" provides quick checks about non-failures and detailed errors can then fit in custom values. But still, I guess we all stuck in this scheme, at least in a last remaining nerve cell which says "hell, but look! wtf...", though this poor neurone ends up being punched and kicked by the rest of the brain folks...
Frederic.
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