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  • $_SERVER['HTTP_HOST'] not set

    - by yes123
    Hi guys, I am getting lot of traffic to my php pages but without the variable $_SERVER['HTTP_HOST'] setted. This traffic is like 1 hit per second. I don't know what it could be, but for reducing server load i am doing this at the top of every php pages: if (!isset($_SERVER['HTTP_HOST'])) exit; Do u know what could cause this? Is it safe to exit whenever http_host is not setted? Can a normal user visit my pages without setting http_host? PHP version: 5.2.0-8, Apache: 2.2.3 Thanks

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  • Python "string_escape" vs "unicode_escape"

    - by Mike Boers
    According to the docs, the builtin string encoding string_escape: Produce[s] a string that is suitable as string literal in Python source code ...while the unicode_escape: Produce[s] a string that is suitable as Unicode literal in Python source code So, they should have roughly the same behaviour. BUT, they appear to treat single quotes differently: >>> print """before '" \0 after""".encode('string-escape') before \'" \x00 after >>> print """before '" \0 after""".encode('unicode-escape') before '" \x00 after The string_escape escapes the single quote while the Unicode one does not. Is it safe to assume that I can simply: >>> escaped = my_string.encode('unicode-escape').replace("'", "\\'") ...and get the expected behaviour?

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  • which regular expressions do you use the most?

    - by markcial
    I'm starting to learn reg exp and i'm just curious to reg exp used by the rest of the people so i can have a thread to look at and learn from. I had started with the eight listed here, i tried to play a little big with firebug and some tutorials and used some in my websites, but i'd like to know some from more experienced people. Thanks!

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  • Converting a macro to an inline function

    - by Rob
    I am using some Qt code that adds a VERIFY macro that looks something like this: #define VERIFY(cond) \ { \ bool ok = cond; \ Q_ASSERT(ok); \ } The code can then use it whilst being certain the condition is actually evaluated, e.g.: Q_ASSERT(callSomeFunction()); // callSomeFunction not evaluated in release builds! VERIFY(callSomeFunction()); // callSomeFunction is always evaluated Disliking macros, I would instead like to turn this into an inline function: inline VERIFY(bool condition) { Q_ASSERT(condition); } However, in release builds I am worried that the compiler would optimise out all calls to this function (as Q_ASSERT wouldn't actually do anything.) I am I worrying unnecessarily or is this likely depending on the optimisation flags/compiler/etc.? I guess I could change it to: inline VERIFY(bool condition) { condition; Q_ASSERT(condition); } But, again, the compiler may be clever enough to ignore the call. Is this inline alternative safe for both debug and release builds?

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  • What's this setting of MATLAB for(which is causing lots of troubles for lots of people)?

    - by Runner
    This setting in PATH: D:\MATLAB\R2007b\bin\win32 Here is a fresh bad affect by this setting for me: http://stackoverflow.com/questions/2712913/why-does-this-program-require-msvcr80-dll-and-whats-the-best-solution-for-this-k And here's an issue reported by another guy: http://groups.google.com/group/ggobi/browse_thread/thread/dacea0fa93dcaf75 What's that setting for and why it's causing so many problems?

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  • Concurrent processes do not utilize all available CPU

    - by metdos
    I run some processes on an EC2 cc2.8xlarge instance which has 32 virtual processors. For some type of processes, when I run 16 processes on parallel, all of them use 100% of CPU cycles. But for other type of processes, they are not using 100% CPU and they finish considerably slower than a single thread. There is no time spend on IO and all data is served from memory. Do you have any idea about the reason of this problem?

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  • Should I pointer-cast from a private derived class to its base class?

    - by skydoor
    I found this from C++FAQ Generally, No. From a member function or friend of a privately derived class, the relationship to the base class is known, and the upward conversion from PrivatelyDer* to Base* (or PrivatelyDer& to Base&) is safe; no cast is needed or recommended. However users of PrivatelyDer should avoid this unsafe conversion, since it is based on a private decision of PrivatelyDer, and is subject to change without notice. How to understand the above words? I don't think the explanation is correct or accurate. I have a code like this class A{ }; class B: private A{ }; int main(){ B *b = new B(); A *a = new A(); a = b; //wrong a = (A*)b; //right }

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  • How to find out how namespace got polluted?

    - by dehmann
    Consider the following little piece of code: // all of these include other headers, lots of code: #include "myheader1.h" #include "myheader2.h" #include <string> void foo() { string s("hello world"); // oh no, why does this compile?? } This compiles, so obviously some of the recursively included header files has a using namespace std; somewhere. How would you go about finding out where that offending line of code is? Just using grep on all header files won't really work because that statement is often used inside a function, where it is safe and won't pollute the rest of the code.

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  • reading files provided via $_GET

    - by Max
    I have a php script which takes a relative pathname via $_GET, reads that file and creates a thumbnail of it. I dont want the user to be able to read any file from the server. Only files from a certain directory should be allowed, otherwiese the script should exit(). Here is my folder structure: files/ <-- all files from this folder are public my_stuff/ <-- this is the folder of my script that reads the files My script is accessed via mydomain.com/my_stuff/script.php?pathname=files/some.jpg. What should not be allowed e. g.: mydomain.com/my_stuff/script.php?pathname=files/../db_login.php So, here is the relevant part of the script in my_stuff folder: ... $pathname = $_GET['pathname']; $pathname = realpath('../' . $_GET['pathname']); if(strpos($pathname, '/files/') === false) exit('Error'); ... I am not really sure about that approach, doesnt seem too safe for me. Anyone with a better idea?

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  • Is it save to read global data from multiple threads?

    - by user362515
    The scenario is as follows: Create an instance of a class (std::map) and sore it as global variable. Spawn threads. Threads read and use the same global instance of the class All spawned threads quit Global class instance is destroyed No mutex, no thread modifies the global class instance. Is it ok? Thank You

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  • Why would Mathematica break normal scoping rules in Module?

    - by Davorak
    As was pointed out in a recent post scoping does not work as expected inside of Module. An example from that thread is: Module[{expr}, expr = 2 z; f[z_] = expr; f[7]] (*2 z$1776*) But the following works as almost as expected. Module[{expr}, expr = 2 z; Set@@{f[z_], expr}; f[7]] (*14*) What language design consideration made wolfram choose this functionality?

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  • Forking with a listening socket

    - by viraptor
    I'd like to make sure about the correctness of the way I try to use accept() on a socket. I know that in Linux it's safe to listen() on a socket, fork() N children and then recv() the packets in all of them without any synchronisation from the user side (the packets get more or less load-balanced between the children). But that's UDP. Does the same property hold for TCP and listen(), fork(), accept()? Can I just assume that it's ok to accept on a shared socket created by the parent, even when other children do the same? Is POSIX, BSD sockets or any other standard defining it somewhere?

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  • Simplifying CASE WHEN SQL statement

    - by kateroh
    Im trying to improve the following CASE statement to calculate the difference only once. I do it to avoid negative numbers: SELECT (CASE WHEN ((SELECT 100 - (SELECT COUNT(CustomerId) FROM Customers)) > 0) THEN (SELECT 100 - (SELECT COUNT(CustomerId) FROM Customers)) ELSE (0) END) This not only looks stupid, but also is not thread-safe. I tried the following, but I get an error message "Invalid column name 'diff'." SELECT (CASE WHEN ((SELECT 100 - (SELECT COUNT(CustomerId) FROM Customers) as diff) > 0) THEN (diff) ELSE (0) END) How can this be simplified? Is there an in-built SQL function that already does this job? EDIT: Sorry, forgot to mention that the select statement is inside of a view declaration, so I cant declare variables.

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  • JavaScript: Is there any "python's Generator" equivalent in JavaScript?

    - by JackSMTV
    Is there any "python's Generator" equivalent in JavaScript? PS: Python's Generator is very memory efficient when we need to do one time iterate through a big array, hash... "Generators are iterables, but you can only read them once. It's because they do not store all the values in memory, they generate the values on the fly" (Python's Generator explained in this thread: The Python yield keyword explained )

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  • MySql. What is there error on this insert+select+where statement?

    - by acidzombie24
    What is wrong with this statement? It works with sqlite and MS sql (last time i tested it) I would like a select unless there is no match with name or email. Then i would like to insert. I have it as one statement because its easy to keep concurrent safe as one statement. (its not that complex of a statement). INSERT INTO `user_data` ( `last_login_ip`, `login_date`, ...) SELECT @0, @14 WHERE not exists (SELECT * FROM `user_data` WHERE `name` = @15 OR `unconfirmed_email` = @16 LIMIT 1); Exception You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE not exists (SELECT * FROM `user_data` WHERE `name` = 'thename' OR `unconfirmed' at line 31

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  • does such a c++ tool exist? [I dont know what to call it]

    - by VSC
    Hello, I am going through the process of trying to figure out how a library of code works. I would like some sort of tool that would analyze the program that I run off of the library and tells me what functions are called in what order by each thread. Does such a tool exist? What google terms would I use to find such a program? Note: Using VS2008/Win7/C++

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  • Byte manipulation in PHP

    - by Michael Angstadt
    In PHP, if you have a variable with binary data, how do you get specific bytes from the data? For example, if I have some data that is 30 bytes long, how do I get the first 8 bytes? Right now, I'm treating it like a string, using the substr() function: $data = //... $first8Bytes = substr($data, 0, 8); Is it safe to use substr with binary data? Or are there other functions that I should be using? Thanks.

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  • How can I dynamically resize the jQuery Colorbox plugin?

    - by James Skidmore
    The AJAX content loaded in a Colorbox has some JavaScript included that resizes things within the content. Colorbox determines its sizing based on the sizes before all of the AJAX happens. How can I make the Colorbox resize after the content has been loaded? Here is a link where someone said that you can call colorbox() again after it's been loaded, but I can't figure out how to do that: http://groups.google.com/group/colorbox/browse_thread/thread/535d21c69e9006b0

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  • Prove 2^sqrt(log(n))= O(n^a)

    - by user1830621
    I posted a question similar to this earlier, although it seemed like it was much easier. I know the underlying principle of Big-O notation says that to prove that 2^sqrt(log(n)) is O(n^a), there must exist a positive value c for which c(n^a) = 2^sqrt(log(n)) for all values n = N. c*n^a >= 2^sqrt(log(n)) c >= 2^sqrt(log(n)) / n^a This number will always be positive so long as n 0. I suppose I could make N = 1 just to be safe. c = 2^sqrt(log(n)) / n^a N = 1 c*n^a = 2^sqrt(log(n) <= 2^log(n) for all values of n >= 1 Now, I know this is incorrect, because I could just as easily claim that the function 2^sqrt(log(n)) is O(n)...

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  • Tell me what's wrong [closed]

    - by steve care
    public class Sample { public static void main (String[]a){ int[] x; x = new int[10]; int i;' int n=0; for (i=0;i<=10;i++){ n++; x[i]=n; System.out.print(x[i] + " "); } } } the problem is I got an error of "Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10"

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  • printf("... %c ...",'\0') and family - what will happen?

    - by SF.
    How will various functions that take printf format string behave upon encountering the %c format given value of \0/NULL? How should they behave? Is it safe? Is it defined? Is it compiler-specific? e.g. sprintf() - will it crop the result string at the NULL? What length will it return? Will printf() output the whole format string or just up to the new NULL? Will va_args + vsprintf/vprintf be affected somehow? If so, how? Do I risk memory leaks or other problems if I e.g. shoot this NULL at a point in std::string.c_str()? What are the best ways to avoid this caveat (sanitize input?)

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