On Thu, Aug 21, 2008 at 12:45 PM, Jim Correia <[EMAIL PROTECTED]> wrote:
> For the sake of completeness (I know Marcel knows the rule), if you are > using the return value of a message send, the value will be undefined > depending on return type when sending a message to nil. See the runtime > documentation for details. As of the 10.5 runtime the zero value guarantee is more well defined (aka review the latest and prior documentation)... --- 10.5 --- - If the method returns an object, any pointer type, any integer scalar of size less than or equal to sizeof(void*), a float, a double, a long double, or a long long, then a message sent to nil returns 0. - If the method returns a struct, as defined by the Mac OS X ABI Function Call Guide to be returned in registers, then a message sent to nil returns 0.0 for every field in the data structure. Other struct data types will not be filled with zeros. - If the method returns anything other than the aforementioned value types the return value of a message sent to nil is undefined. --- older --- A message to nil also is valid, as long as the message returns an object, any pointer type, void, or any integer scalar of size less than or equal to sizeof(void*); if it does, a message sent to nil returns nil. If the message sent to nil returns anything other than the aforementioned value types (for example, if it returns any struct type, any floating-point type, or any vector type) the return value is undefined. You should therefore not rely on the return value of messages sent to nil unless the method's return type is an object, any pointer type, or any integer scalar of size less than or equal to sizeof(void*): -Shawn _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
