This will probably work on most systems, but it is Undefined Behaviour. Quoth the Standard: 5.2.5.3 If E1 has the type “pointer to class X,” then the expression E1->E2 is converted to the equivalent form (*(E1)).E2 […] And: 5.2.5.1 A postfix expression followed by a dot . or an arrow ->, optionally followed by the … Read more
but I can’t see anything in the standard that therefore allows me to reinterpret_cast between them, even though that seems like the reasonable interpretation of “value representation”. Is this technically allowed by the standard? No. The standard is clear (see [basic.lval] p10) about which types can be aliased, and layout-compatible types are not included. If … Read more
Communication with Fred J. Tydeman, Vice-char of PL22.11 (ANSI “C”), on comp.std.c shed some light on this: fscanf An input item is defined as the longest sequence of input characters […] which is, or is a prefix of, a matching input sequence. (7.19.6.2 P9) This makes “0x” the longest sequence that is a prefix of … Read more
Essentially, a denormalized float has the ability to represent the SMALLEST (in magnitude) number that is possible to be represented with any floating point value. That is correct. using denormalized numbers comes with a performance cost on many platforms The penalty is different on different processors, but it can be up to 2 orders of … Read more
You can do this: if(‘draggable’ in document.createElement(‘span’)) { alert(“Drag support detected”); } You can see a quick demo test using the above check here. Also, there’s a nice feature detection (not browser detection, yay!) list that’s fairly well maintained here in case you’re looking for other HTML5 features as well.
I recently worked at a company which still used a version of the PDP-10, and a port of GCC to that platform. The 10 we used had a few of the attributes you list: Integers are not 32 or 64 bits they are 36 bits wide. Padding bits are used for some representations. For extended … Read more
The freedom to implement things in the most natural way on each processor. I imagine that c in particular has conforming implementations on more different architectures than any other language. Abiding by a ABI optimized for the currently common, high-end, general-purpose CPUs would require unnatural contortions on some the odder machines out there.
for library: phonenumbers (pypi, source) Python version of Google’s common library for parsing, formatting, storing and validating international phone numbers. The readme is insufficient, but I found the code well documented.
use backticks when you want to easily capture the output of a program in a variable. you probably only want to use this for short-running programs, because this will block. system is convenient in two different cases: a. You have a long running program and you want the output to print as it runs (e.g. … Read more
UPDATE: This answer was written in 2010 and as anticipated std::auto_ptr has been deprecated. The advice is entirely valid. In C++0x std::auto_ptr will be deprecated in favor of std::unique_ptr. The choice of smart pointer will depend on your use case and your requirements, with std::unique_ptr with move semantics for single ownership that can be used … Read more