Objective-C: enforce call to super when overriding specific super methods in subclass
Give warning when [super method] is not called
Computer keeps restarting by itself Can I legally downgrade from Win 7 64 bits to Win 7 32 bits? Possible Duplicate:          Tired of the unstable Win 7 64bit I got when I purchased my laptop (it was impossible to find a powerful laptop with Win 7 32 bits).  Can I legally downgrade from Win 7 64 bits to Win 7 32 bits? The key/activation will work?    Details: Everybody comments about the stability of Win 64.  Well, I made a mistake. Is not that Win 64 is unstable (it never crashed). It just works very poor. It feels choppy. Compiling a large program (on an old AMD desktop PC) takes 1.5 seconds on Win 32. The same program compiles on Win 64 in 4-5 seconds in this new and "powerful" laptop. All programs are less responsive. Is $\cot(z)-\frac1z$ bounded on a given circle? Why do you cast downvotes on answers? This is a question which started off with a , then turned into an , and now it's a question in its own right (as suggested by Jeff). I'm not sure where it could go from here :)  It's obvious that different people cast downvotes for different reasons. (Upvotes are less controversial, generally.) Here are some possible reasons:   Answer is wrong Answer is misleading (may be technically accurate, but will lead to readers making mistakes) Answer doesn't match the question (e.g. a C# answer to a question about Java) Answer doesn't really address the question, e.g. suggesting a completely different solution, even if the question specifies that there are good reasons why the current approach has to be followed Answer is okay, but not as good as another one which currently has fewer votes Answer appears to be plagiarised from existing answers. Answer is by someone I don't like. Answer is abusive (profanity, spam etc). No reason, I just felt like it. I'm a , and prefer down to up. Have you considered down? Ideological grounds: answer suggests a technology I don't like, or expresses a negative opinion of a technology I do like   Personally I go with 1, 2 and 8 - although I'll add comments suggesting changes in various other situations.  Have I missed anything? What do you do, and why? What are the net benefits (to you, the world in general, and the answerer) from your approach? Footnote citations in biblatex ignore spacing before the citation command; how can I have the same behavior for all footnotes in a document?  Here's a MWE demonstrating the issue:  \documentclass{article} \usepackage[style=verbose-trad2]{biblatex} \addbibresource{biblatex-examples.bib} \begin{document} Spacing is fine before citations     \autocite{kant:kpv}  but not before footnotes    \footnote{A footnote \autocite{kant:ku}}. \end{document} Add Item to Finder Sidebar Two different solutions to integral One of the first things ever taught in a differential calculus class:   The derivative of $\sin x$ is $\cos x$. The derivative of $\cos x$ is $-\sin x$.   This leads to a rather neat (and convenient?) chain of derivatives:   sin(x) cos(x) -sin(x) -cos(x) sin(x) ...   An analysis of the shape of their graphs confirms some points; for example, when $\sin x$ is at a maximum, $\cos x$ is zero and moving downwards; when $\cos x$  is at a maximum, $\sin x$ is zero and moving upwards.  But these "matching points" only work for multiples of $\pi/4$.  Let us move back towards the original definition(s) of sine and cosine:  At the most basic level, $\sin x$ is defined as -- for a right triangle with internal angle $x$ -- the length of the side opposite of the angle divided by the hypotenuse of the triangle.  To generalize this to the domain of all real numbers, $\sin x$ was then defined as the Y-coordinate of a point on the unit circle that is an angle $x$ from the positive X-axis.  The definition of $\cos x$ was then made the same way, but with adj/hyp and the X-coordinate, as we all know.  Is there anything about this basic definition that allows someone to look at these definitions, alone, and think, "Hey, the derivative of the sine function with respect to angle is the cosine function!"  That is, from the unit circle definition alone.  Or, even more amazingly, the right triangle definition alone.  Ignoring graphical analysis of their plot.  In essence, I am asking, essentially, "Intuitively why is the derivative of the sine the cosine?" How does one write on the outside of a circle?  I am looking for sample files/packages which imitate a magazine lay-out. Specifically a page with two columns having a circular picture between the two columns.    Example of the desired layout, created using Word: When validating a field manually from my form a error is displayed but the field doesn't get red. For the first parameter i used the name of the input element. DRUPAL 7  if($form_state['values']['panes']['webform_nid31'][0]['contact_person'] == '') {     form_set_error('panes[webform_nid31][0][contact_person]', t('You must select a name for this group of settings.'));   } Winforms Textbox - Using Ctrl-Backspace to Delete Whole Word probability of $k$ boxes contain exactly $1$ ball Prove that $f$ continuous and $\int_a^\infty |f(x)|\;dx$ finite imply $\lim\limits_{ x \to \infty } f(x)=0$ How can I determine that I am looking at the block I need? How to close aberrant tooltips in Windows So, here I am, trying to watch The Cleveland Show (TM).      And, as happens from time to time, some program or another has left a modal tooltip.  I don't know which program; how can I lose the tooltip, short of logoff/reboot?  Currently happening on Windows 10, but I have seen it on other versions. Number of elements in a finite $\sigma$-algebra Many times it takes me a while to properly compose my question before posting. Sometimes it's just a jumble of ideas and concepts, and is not something I'd want seen immediately. However, there is no way to save a partial question unless you post it.  This should work exactly like it does in Gmail. There, once you start composing your question, it's autosaved as a draft. If your browser crashes or you need to come back later to complete it, it will be there for you to finish and post later.  Optionally, allow multiple draft questions and a page to edit/delete them. If needed, make them expire after some amount of time. How to control the coordinates in Tikz & Matrix? I use Tikz with Matrix because I need to draw arrows and write on and beside the matrix. However, I don´t control the coordinates well other than using trail and error. For instance in the matrix below I have put an X at (0,0) and it is not in the centre of the matrix. However, if the matrix is 4x4 than it is in the centre. Is there any convenient way to know the coordinates? \documentclass[border=1cm]{standalone}  \usepackage{tikz} \usetikzlibrary{matrix}   \begin{document}  \begin{tikzpicture} \matrix(m) [matrix of math nodes, nodes in empty cells, nodes={minimum size=1cm, outer sep=0pt, text height=1.5ex, text depth=.25ex}] {  36     &amp;   &amp; 32    &amp;   &amp; 33    &amp;   \\         &amp;   &amp;       &amp;   &amp;       &amp;   \\  10     &amp;   &amp; 8     &amp;   &amp; 7     &amp;   \\         &amp;   &amp;       &amp;   &amp;       &amp;   \\  12     &amp;   &amp; 17    &amp;   &amp; 16    &amp;   \\         &amp;   &amp;       &amp;   &amp;       &amp;   \\  23     &amp;   &amp; 15    &amp;   &amp; 16    &amp;   \\     &amp;   &amp;   &amp;       &amp;   &amp;       &amp;   \\ };  \draw (m-1-1.north west) rectangle (m-8-6.south east);    % Lineas horizontales \foreach \i in {2,4,6,8} {   \draw (m-\i-1.south west) -- (m-\i-6.south east); }  % Lineas verticales \foreach \j in {2,4,6} {   \draw (m-1-\j.north east) -- (m-8-\j.south east); }  % dual ui \node [font=\color{red}] at (3.5,3) {$\ge 10$}; \node [font=\color{red}] at (3.5,1) {$\ge 8$}; \node [font=\color{red}] at (3.5,-1) {$=4$}; \node [font=\color{red}] at (3.5,-3) {$=3$};  % dual vj \node [font=\color{red}] at (-2.5,-5) {$\le12$}; \node [font=\color{red}] at (-0.5,-5) {$=12$}; \node [font=\color{red}] at (1.5,-5) {$=6$};  \node [font=\color{red}] at (0,0) {X};  \end{tikzpicture}     \end{document} "Me and my wife" or "my wife and me" Alternative set theories This is a (soft!) question for students of set theory and their teachers.   OK: ZFC is the canonical set theory we all know and love. But what other, alternative set theories, should a serious student encounter (at least to the extent of knowing that the theory exists, and about why it is thought interesting)?  Suggestions might be SP (Scott-Potter), NBG, NF, ZFA, IST, ETCS (for a few sentences of explanation, see   But what would be on your list of alternative set theories would be it good for advanced students to hear about, if only briefly?