scope

问题 I have the following lines of code: struct c_obj_thing *object = NULL; c_obj_initalizer(object); // at this point, (object == NULL) is 'true' printf("Value: %d\n", object->value); // this segfaults Here is the definition for c_obj_initalizer: int c_obj_initalizer(struct c_obj_thing *objParam) { objParam = malloc(sizeof(struct c_obj_thing)); objParam->pointerThing = NULL; objParam->value = 0; return 0; } Why does the malloc in the c_obj_initalizer method not stay attached to the pointer passed

问题 I am trying to create a :readable scope in my Page model to return all the Pages that the current_person has sufficient 'rank' to read: scope :readable, lambda { |current_person| joins(:role_readable) .where(:role_readable[:rank].gte(current_person.roles.first.rank) ) } I've tried many scope permutations, including this one, with no success (the one above gives a "can't convert Symbol into Integer" error). The problem is made more complex because Users (which handle authentication etc. /

问题 I have a several variables which are assigned to the same function . The property 'name' is "" as this function is anonymous; There also isn't a function call involved, and as such no callee. Is there a way in JS to obtain the variable's name, through a self-implemented reflection algorithm? e.g. var x = function(){} var myUnknownNamedVar1 = myUnknownNamedVar2 = x; Background : for space efficiency, thousands of variable names are assigned to the same 'static' function as a lazy-loaded stumps

问题 See code below. Put both files in the same directory and run Form1.ps1 from the PS ISE As you can see, the (local) variable $localVar is defined in the event handler $button2_Click . As such, I assumed $localVar would not/could not exist outside the scope of $button2_Click with scope defined by the braces that define the event handler. However, as you can see, I use the contents of $localVar to load $textbox2.Text in the function fA . When you click the Test button, both textboxes display the

问题 I've been struggling for a while on this. I'm a bit of a newbie, but i lurked a lot and still couldn't find a solution to my problem, so I decided to post my question here. I'm binding a pivot to a collection of objects I want to display to create a gallery. Here is my pivot control bound to a list called gallery, where each object contains 2 strings (url and description). <controls:Pivot ItemsSource="{Binding gallery}" Grid.Row="0" x:Name="galleryPivot"> <controls:Pivot.ItemTemplate>

问题 declaring a variable in a class (outside of a function) : all class functions can access it (basically a public variable) declaring a variable inside a function inside a class : only that function can access it (its in that functions scope) declaring a variable with self.(variable name) inside a function inside a class : all class functions can access it (how is this different from global (variable name)?) and since there is no private / protected, everything is public, so everything

问题 When a User checks off :good in the _form <%= f.text_field :result_value %> <%= f.date_select :date_value %> <%= f.check_box :good %> how can we render the font color in the index of that result ( :result_value & :date_value ) to green? result.good below pulls up true or false in the index. I'll take that out once we represent true or false with colors: true = green, false = red (default color). <% averaged.results.each do |result| %> <li> <%= result.result_value %> <%= result.date_value

问题 In ruby, module , class , and def keywords define a new scope. I'm confused as to why local variables defined in a block do not exist outside of the block. Is a block argument another scope gate? For example: (1..2).each { |n| numer = 'czesc' } numer # => NameError: undefined local variable or method `czesc' for main:Object Or more simply: def kon; end kon { kot = 3 } kot # => NameError: undefined local variable or method `kot' for main:Object I thought, maybe it's not persisted because it's

问题 How many scopes are there in Struts 2 applications? And is it good if we use session and request scope there? How action scope work for session and request both? 回答1: Struts 2 is running a container, it has scopes for beans. More about bean scopes is in this question. All other scopes are servlet scopes. Struts uses indirect access to these scopes using it's own structures. For example a set tag uses these scopes: The scopes available are as follows : application - the value will be set in

问题 Well, I read in my handy PHP book that it's very important to be able to distinguish between reference and variable parameters. The book says that the original value of parameterized variables are preserved when the variable is changed, and the original values of parameterized references change when the reference is changed. It says that's the key difference, if I am reading right. Well, I'm wondering when each is more useful than the other. How do I know when to use variables and when to use