reference

问题 Please can any one advise me if there is an object in .net that can be used to get a list or references to all objects that are currently in scope for an object. For example if the code is currently executing in a method, what objects declared in this method are currently instanciated and alive and what objects that are declared at class level have been instanciated already and are alive? Also I know I can test each object declared explicitly for a null reference, but I am looking for

问题 I am writing a Perl script that gets data from a changing outside source. As data is added or removed from this outside source I would like the data structures in my Perl script to mirror the changes. I was able to do this by creating objects that store the data in a similar fashion and synchronizing the data in those objects whenever I try to access the data in my Perl script. This works great, and gets any new data that is added to this external source; however a problem arises when any

问题 This question already has answers here : Python list problem [duplicate] (2 answers) Closed 5 years ago . Here is the example, >>> x = ["a","b","c"] >>> yy = [x] * 3 >>> yy [['a', 'b', 'c'], ['a', 'b', 'c'], ['a', 'b', 'c']] >>> yy[0][0] = 'A' >>> yy [['A', 'b', 'c'], ['A', 'b', 'c'], ['A', 'b', 'c']] >>> When i do yy[0][0] = 'A' , it replaced to all the first element of the sub-list. What i got from here is when i do [x] * 3 , it creates some reference to list x but not sure how really it

问题 This is a follow up on an answer in this question: What kind of optimization does const offer in C/C++? (if any) In the top voted answer, the following is stated: When you declare a const in your program, int const x = 2; Compiler can optimize away this const by not providing storage to this variable rather add it in symbol table. So, subsequent read just need indirection into the symbol table rather than instructions to fetch value from memory. NOTE:- If you do something like below:- const

问题 I am Compiling this using g++ and a makefile. The g++ version is 4.1.2 20080704. Here is the simplified code which still contains the error: #ifdef __cplusplus extern "C" { #endif class MyClass { public: MyClass() {}; MyClass& operator=(MyClass&); static MyClass& instance() { return log; }; private: static MyClass log; }; //MyClass MyClass::log; int main() { MyClass& myClass = MyClass::instance(); return 0; } #ifdef __cplusplus } //extern "C" #endif When I compile with 'g++ MyClass.cpp" I get

问题 I want to get information of an object from a previous keyframe. _root. works only for objects on the same keyframe as the code right? 回答1: Your object doesn't exist one you leave the keyframe that created it, unless the object was added with ActionScript. You'll have the place the object on its own layer and extend the keyframe to reach the point where you're trying to access it, or as mentioned create it with ActionScript. 来源： https://stackoverflow.com/questions/8934346/how-to-refer-to

问题 I have a Xamarin Forms cross platform solution. When I build the solution, the iOS project can't resolve the reference: C:/Program Files (x86)/Reference Assemblies/Microsoft/Framework/Xamarin.iOS/v1.0/Facades/System.IO.FileSystem.Watcher.dll even though it is physically there. All the other projects build just fine. I can't find a reference to the DLL or the class anywhere in the solution files. I don't need the capability. Ideas? Thanks. 回答1: I had the exact same issue. I found out that the

问题 I need to pass in a variable,list and a hash to a subroutine, and get back changes from it without returning. This code doesnt do the job. sub foo{ my $one = {$_[0]}; my @list = @{$_[1]}; my %hash = %{$_[2]}; print("\n inside foo: ${one}\n"); print("\n inside foo: $one @list $hash{'key'}\n"); $one = 2; @list = (4,5,6); my %hash2; $hash2{'key'} = 'valueModified'; %hash = %hash2; print("\n inside foo after Mod: $one\n"); print("\n inside foo after Mod: $one @list $hash{'key'}\n"); } my $one = 1

问题 I am writing a function that takes a mysqli_result and adds all of the returned columns into an associative array in my result object. As of right now everything that is returned via the mysqli::multi_query is in string format, while the description as to what value type the value should be is kept in the array of objects returned by mysqli::fetch_fields. I feel that so far this is pretty confusing so let me code it out if ($mysqli->multi_query($inputQuery)) { if ($result = $mysqli->store

问题 I have this: a.cpp int localfunction () { return 1; } int local_symbol = localfunction(); b.cpp void thirdfunction () {}; main.cpp void main () { thirdfunction (); } When I compile this in a main executable everything works (even with optimizations), and the localfunction is executed at startup even if I don't call it directly. Now, in Visual C++ and GCC , I put a.cpp and b.cpp in a static library (.lib). localfunction is no more executed/defined. From what I understand the symbol is detected