global-variables

问题 When I try to compile the following with g++: const int zero; int main() { return 0; } I get an error about an uninitialized const 'zero' . I thought that global variables were default initialized to 0 [1] ? Why isn't this the case here? VS compiles this fine. [1] For example, see https://stackoverflow.com/a/10927293/331785 回答1: My gcc is slightly more verbose: $ g++ zeroconst.c zeroconst.c:1:11: error: uninitialized const ‘zero’ [-fpermissive] We see that -fpermissive option will allow this

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 3 years ago . I had a couple thoughts on this. The first is that allocating global variables may be faster, since they are only allocated once, at the time the program is first spawned, whereas local variables must be allocated every time a function is called. My second thought is that since

问题 From a comment: " global in Python basically means at the module-level". However running this code in a file named my_module.py : import my_module as m foo = 1 m.bar = m.foo + 1 if __name__ == "__main__": print('foo:', foo) print('m.foo:', m.foo) print('m.bar:', m.bar, '\n') for attrib in ('foo', 'bar'): print("'{0}' in m.__dict__: {1}, '{0}' in globals(): {2}".format( attrib, attrib in m.__dict__, attrib in globals())) Output: foo: 1 m.foo: 1 m.bar: 2 'foo' in m.__dict__: True, 'foo' in

问题 How does one list/view/clear persistent variables in MATLAB? I'd like to see persistent variables not for a particular function, but for all functions that have persistent variables currently in memory. I've tried things like whos('persistent') and whos('global') with no luck. 回答1: If you want to clear a persistent from outside of the function within which it's defined, then you need to clear the function itself: clear functionNameWithPersistentVariable Or clear all (unlocked) functions from

问题 Is there a standard way to code a module to hold global application parameters to be included in every other package? For instance: use Config; ? A simple package that only contains our variables? What about readonly variables? 回答1: There's already a standard Config module, so choose a different name. Say you have MyConfig.pm with the following contents: package MyConfig; our $Foo = "bar"; our %Baz = (quux => "potrzebie"); 1; Then other modules might use it as in #! /usr/bin/perl use warnings

问题 I have a function that i'm calling from module. Within the function the two variables i'm trying to access are made global. When I run the module in IDLE by itself I can still access the variables after the function ends, as expected. When I call the function in the code that I have imported the module into I can't access the variables. #module to be imported def globaltest(): global name global age name = str(raw_input("What is your name? ")) age = int(raw_input("What is your age? ")) The

问题 I am working on a text-based game to get more practice in Python. I turned my 'setup' part of the game into a function so I could minimize that function and to get rid of clutter, and so I could call it if I ever wanted to change some of the setup variables. But when I put it all into a function, I realized that the function can't change global variables unless you do all of this extra stuff to let python know you are dealing with the global variable, and not some individual function variable

问题 I have a linux bash script with a function: myfunctiona () { local MYVAR1="one" local MYVAR2="two" echo $MYVAR1 # The line beneath is the line in question! local MYVAR1=$MYVAR1$MYVAR2 } When I want to give the LOCAL variable MYVAR1 in the function myfunctiona a new value, do I have to write local MYVAR1=$MYVAR1$MYVAR2 or can I also write MYVAR1=$MYVAR1$MYVAR2 With the second line without "local" do I create a global variable with the same name? 回答1: Once you've defined a local variable you

问题 I don't know if "global" is the right word, but what I have to do is: define a variable that I can use in many parts of the template. Example: I have to define a variable that contains the ID of a static page $page_id = 34 and I have to use it in different template parts, with functions like get_page_link($page_id) I found many way to do it (PHP define(), in function.php, global, ...) but I ask what is the most secure , in your opinion. 回答1: You can either define it in wp-config file (which

问题 I have a singleton object in iOS that when instantiated parses a CSV file and then holds the results. I would like to make this object universally accessible and I would like it to not be released from memory until the app quits. I am running ARC so I cannot do manual retains. Is there a way I can do this so it will work with ARC? Header File: #import <Foundation/Foundation.h> #import "CHCSV.h" #import "RCParserObject.h" @interface ParserStore : NSObject <CHCSVParserDelegate> { // CSV