<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">The compiler initializes the first word of every block to one of two symbols (the other being <span class="Apple-style-span" style="font-family: Monaco; font-size: 10px; ">_NSConcreteStackBlock)</span>, that being one of them, so as to enable Objective-C treating blocks as objects if and when the objc runtime is loaded. The blocks runtime for the most part ignores these values until such a time. A block copy operation will use another symbol, so in total I think you'll need <span class="Apple-style-span" style="color: rgb(53, 131, 136); font-family: Monaco; font-size: 10px; ">_NSConcreteMallocBlock <span class="Apple-style-span" style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; ">also.</span></span><div>Blaine</div><div><br><div><div>On Jan 12, 2010, at 11:15 AM, david raila wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><br>Trying blocks on a x64 linux gives undefined reference to <br>`_NSConcreteGlobalBlock', am I missing a library<br>or something?<br><br>Alternatively, what are the plans/timetable for an implementation of <br>C++0x lambdas in clang?<br><br>Thanks.<br><br>_______________________________________________<br>cfe-dev mailing list<br><a href="mailto:cfe-dev@cs.uiuc.edu">cfe-dev@cs.uiuc.edu</a><br>http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev<br></div></blockquote></div><br></div></body></html>