Russel: Thank you a curly bracket was missing. How could I not notice. Valdis: I shall take your suggestions. Mandeep: Thank you for that enlighting ideas
Regards, Saket Sinha On Mon, Jul 15, 2013 at 7:52 PM, <[email protected]> wrote: > On Mon, 15 Jul 2013 17:39:15 +0530, Mandeep Sandhu said: > > > #define push_root() \ > > recursive_mutex_lock(&context->id_lock); \ > > context->uid = current->fsuid; \ > > context->gid = current->fsgid; \ > > do { \ > > struct cred *new1 = prepare_creds(); \ > > //make changes to any member of this structure \ > > commit_creds(new1); \ > > } while(0); > > Actually, this has 3 problems: > > 1) You have a call to mutex_loc() that doesn't get unlocked. This Is Bad. > > 2) If you're using the 'do { foo } while (0)' trick, you want to > put the *whole thing* inside the { } (Hint - you can put local variable > definitions inside the curlies as well). > > 3) Leave the ; off the 'while (0)' in the macro definition, because: > > > int main() > > { > > printf("in main\n"); > > pushme > > return 0; > > } > > Somebody will forget and put a ; after pushme - and in some contexts, the > additional ; will then cause issues. > >
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