c++ static local variable initialization

such a variable is initialized the first time control passes through its declaration; such a variable is considered initialized upon the completion of its initialization. So two copies of static variable i exist. Important points about static keyword: 1. When incrementAndPrint() is finished running, the variable goes out of scope and is destroyed. What is this fallacy: Perfection is impossible, therefore imperfection should be overlooked, central limit theorem replacing radical n with n, 1980s short story - disease of self absorption. What is thread safe or non-thread safe in PHP? CGAC2022 Day 10: Help Santa sort presents! This means the variable is now created at the start of the program, and destroyed at the end of the program (just like a global variable). Variables to be zero-initialized are placed in the. Something like. But the two calls do something different, which can be very confusing if the difference is more than a changed prompt. The variable is initialized before main () kicks in and later you have all the types in the factory. Dont use static local variables to alter flow. This should also be OK, you can find in standard following footnote: The implementation must not introduce any deadlock around execution of the initializer. Dynamic initialization The language also distinguishes between variables What is a static storage class in C language? It should not be changed. One of the most common uses for static duration local variables is for unique ID generators. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. If you notice a defect, it can be near impossible to distinguish which object is having problems. The term static is one of the most confusing terms in the C++ language, in large part because static has different Disconnect vertical tab connector from PCB. An argument is a way for you to provide more information to a function. Cost of thread-safe local static variable initialization in C++11? Upon successful construction the flag will be set to "is constructed". Agree The term static is one of the most confusing terms in the C++ language, in large part because static has different meanings in different contexts. Formally, C++ initializes such variables in three phases: 1. static int variable_name = 10; // initializing the value of static integer variable Note: The value of a static variable can be reinitialized wherever its scope exists. If you do the same thing again, youd expect the same behavior as last time. Static variables have a property of preserving their value even after they are out of their scope! Also, have a look at the old thread Are function static variables thread-safe in GCC? Are C++11 thread_local variables automatically static? Are defenders behind an arrow slit attackable? Therefore, they must be initialized with a constant value. Books that explain fundamental chess concepts. Does balls to the wall mean full speed ahead or full speed ahead and nosedive? A better way of implementing getInteger is to pass s_isFirstCall as a parameter. What are class variables, instance variables and local variables in Java? Only in C++11 and later can a type with a non-trivial constructor be considered: In "Effective C++", Meyers describes the class in your question literally as: This would imply that given the C++ Standard being correct, "Effective C++" can also remain correct even after C++11 as long as the supplied constructor for FileSystem is not constexpr. getInteger() is not reusable, because it has an internal state (The static local variable s_isFirstCall) which cannot be reset from the outside. Constant initialization is usually applied at compile time. Constant initialization (3.6.2) of a block-scope entity with static 2) Otherwise, non-local static and thread-local variables are zero-initialized. Global and static variables are initialized to their default values because it is in the C or C++ standards and it is free to assign a value by zero at compile time. What effect does it have on a local variable? Help us identify new roles for community members, Proposing a Community-Specific Closure Reason for non-English content. The Psychology of Price in UX. "Magic statics" are finally coming with VS 2015: @Nawaz: WHy does the constructor have to be thread-safe? Static initialization of local variables. These variables are allocated in . No problem, just put it back into the microwave and press +1 to run it for a minute. storage duration, if applicable, is performed before its block is Zero initialization 2. Find centralized, trusted content and collaborate around the technologies you use most. If the initialization of a non-inline variable (since C++17) is deferred to happen after the first statement of main/thread function, it happens before the first odr-use of any variable with static/thread storage duration defined in the same translation unit as the variable to be initialized. Should I give a brutally honest feedback on course evaluations? #, Sep 25 '08 If an object that has static storage duration is not initialized Note that the above programs compile and run Using a lambda, function call, or constructor doesn't change the thread-safety of the initialization. Is local static variable initialization thread-safe in C++11? If someone reads the code in main() without reading the implementation of getInteger(), theyd have no reason to assume that the two calls to getInteger() do something different. static int x = 5; static int y; The static variable x is stored in the initialized data segment and the static variable y is stored in the BSS segment. A program that demonstrates static variables in C is given as follows A static constructor is called automatically. However, every implementation I've worked with uses a lock around the constructor (with a twice-checked flag) to guarantee thread-safety. Note: Visual Studio did not implement this aspect of C++11 until VS-2015. The static variables are alive till the execution of the program. This code does what its supposed to do, but because we used a static local variable, we made the code harder to understand. Is it really correct to talk about initialization at compile-time? Yes, indeed there are 3 phases (in the Standard). Static local variables can be made const (or constexpr). storage duration under the same conditions that an implementation is Imagine a program where you have many similar objects (e.g. @balki, GCC has implemented it for nearly a decade. We do not currently allow content pasted from ChatGPT on Stack Overflow; read our policy here. those that must be initialized at runtime) in a way that they are created when they are #include using namespace std; template void fun (const T& x) { static int i = 10; cout << ++i; Then there's a footnote: WebWhy are global variables initialized to zero? The syntax for initializing the value of the static variable in C programming language is given below. A look at the generated assembler code helps. Static local variables are only initialized the first time the code is executed, not on subsequent calls. With a const/constexpr static local variable, you can create and initialize the expensive object once, and then reuse it whenever the function is called. The default value of static variable is 0. If the constructor of AppSettings recursively enters AppSettings::GetInstance(), the behavior is undefined. Is there a higher analog of "category with all same side inverses is a groupoid"? The scope isn't as constrained as it was in 'C' but that shouldn't be a real problem. The global variables which are outside the block are visible up to the end of the program. How to Design for 3D Printing. Connect and share knowledge within a single location that is structured and easy to search. The standard is silent on the question of how function-level statics are constructed when the function is called on multiple threads. storage duration in namespace scope (3.6.2). Constant initialization describes initialization that can be determined at compile-time. Can we initialize static variable in constructor? if you never call a function emulating a non-local static object, you never incur the cost of constructing and destructing the You can assign these numbers as unique IDs for your objects. The compilers are allowed to initialize dynamically-initialized variables as part of static initialization (essentially, at compile time), if the following conditions are both true: Because of the rule above, if initialization of some object o1 refers to an namespace-scope object o2, which potentially requires dynamic initialization, but is defined later in the same translation unit, it is unspecified whether the value of o2 used will be the value of the fully initialized o2 (because the compiler promoted initialization of o2 to compile time) or will be the value of o2 merely zero-initialized. Appropriate translation of "puer territus pedes nudos aspicit"? Say you press the +1 button on your microwave and the microwave adds 1 minute to the remaining time. That means that we can't say for sure if the fs variable is or is not initialized even if we don't call to the function tfs(). What effect does using keyword static have on a global variable? msdn.microsoft.com/en-us/library/vstudio/, blogs.msdn.com/b/vcblog/archive/2014/11/17/. In C, static and global variables are initialized by the compiler itself. How to implement multithread safe singleton in C++11 without using . If control enters the declaration concurrently while the variable is being initialized, the concurrent execution shall wait for completion of the initialization. A local static variable is a variable, whose lifetime doesnt stop with a function call where it is declared. The static variable is a variable that is capable of retaining its value between multiple numbers of function calls in a program. Can we modify a static variable in C in another function after we send it as a parameter? No, it doesnt work that way. Consequently, this program outputs: Now consider the static version of this program. Help us identify new roles for community members, Proposing a Community-Specific Closure Reason for non-English content, Local Static variable initialization is thread safe. This page has been accessed 663,685 times. Is it possible to hide or delete the new Toolbar in 13.1? Is Meyers' implementation of the Singleton pattern thread safe? Is the Designer Facing Extinction? In C++98/03, the construction was not guaranteed to be thread safe. void f(int a) {static int b; b+=a;} Shall 'b' be initialized to zero What is the current state of support for 'thread_local' across platforms? If you used a normal local variable, the variable would be created and initialized every time the function was executed. If the compiler can see how to construct instance "at compile time", it is allowed to. David Rodrguez - dribeas 199572 Why is it so much harder to run on a treadmill when not holding the handlebars? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. WebWe can also initialize the value of the static variable while declaring it. All function calls share the same copy of local static variables. Static local variables with non-constexpr initializers are initialized the first time the variable definition is encountered (the definition is skipped on subsequent calls, so no reinitialization happens). Replies have been disabled for this discussion. 2022 ITCodar.com. Is the constructor of variable lg guaranteed to run only once? Connecting three parallel LED strips to the same power supply, MOSFET is getting very hot at high frequency PWM. There are two forms of static initialization: 1) If possible, constant initialization is applied. Both static and global variable behave same to the generated object code. Learn more. @Chris: Deterministic initialization and avoidance of the static initialization order fiasco. So it will be performed when the block first entered? Why does the distance from light to subject affect exposure (inverse square law) while from subject to lens does not? Thanks for helping to make the site better for everyone. Initialization includes the evaluation of all subexpressions within the initializer and the creation of any temporary objects for function arguments or return values. The order of destruction of non-local variables is described in std::exit. All function calls But this time the microwave adds only 1 second and not 1 minute. Allow non-GPL plugins in a GPL main program, Books that explain fundamental chess concepts. The compiler checks for you, if the variable is definitly set. Everything To Know About OnePlus. 5 Key to Expect Future Smartphones. Suppose we want to add subtraction to the calculator such that the output looks like the following: We might try to use getInteger() to read in the next two integers like we did for addition. Speaking for java: local variables must be initialized before you can access it, because it's a safety gain. Thanks for contributing an answer to Stack Overflow! If multiple threads attempt to initialize the same static local variable concurrently, the initialization occurs exactly once (similar behavior can be obtained for arbitrary functions with std::call_once). Normally in a logging system, client code use it as macro, like LOG << "your log" , and the macros have to have an deterministic access to the logger 2. C# doesn't have a direct substitute, the closest match is adding a static private member to your class. Let us clarify them before continuing: Zero Initialization: the memory is filled with 0s at the byte C++11 (and above) guarantees no data races between multiple threads trying to initialize a static local variable. such a variable is initialized the first time control passes through its declaration; such a variable is considered initialized upon the completion of its initialization. I'm not that great with assembler, but I can see that in the first version v has a lock around it and get is not inlined whereas in the second version get is essentially gone.You can play around with various compilers and optimization flags, but it seems no compiler is able to inline or optimize out the locks, even though the program is obviously single threaded.You can add static to get which makes gcc inline get while preserving the lock. 3. Static Initialization; Dynamic Initialization. --fno-threadsafe-statics also worth mentioning. (Enter another integer instead of Enter an integer). Is asignment of a local static reference thread-safe? If multiple threads attempt to initialize the same static local variable concurrently, the initialization occurs exactly once (similar behavior can be obtained for arbitrary functions with std::call_once). WebLocal variables with static duration are zero-initialized or POD initialized with constant expressions when (or before) the block is entered for the first time (as with static initialization ), while for the rest of the initializations are performed the first time that control passes over through it's declaration. This means your CreateEmployee() will always return the same Employee instance. 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Your meal is warm and youre happy. Unnamed/anonymous namespaces vs. static functions. Because implementation is permitted to perform early initialization as for variables with static storage duration. Static initialization 3. For example, in the following program there are two instances: void fun (int ) and void fun (double ). However, as long as anything from a translation unit is odr-used, all non-local variables whose initialization or destruction has side effects will be initialized even if they are not used in the program. I mean, constant initialization's performed when program is being started (or deffered to some statement of. We also discussed how the static keyword gives a global identifier internal linkage, which means the identifier can only be used in the file in which it is defined. Static variables offer some of the benefit of global variables (they dont get destroyed until the end of the program) while limiting their visibility to block scope. The default value of static variable is zero. How does the Chameleon's Arcane/Divine focus interact with magic item crafting? What is a structure at local scope in C language. Why did the Council of Elrond debate hiding or sending the Ring away, if Sauron wins eventually in that scenario? Webstatic variable in c static keyword in c: Keyword static is used for declaring static variables in c. This modifier is used with all data types like int, float, double, array, pointer, structure, function etc. never incur the cost of constructing and destructing the object, When applied to a local variable, the static keyword defines the local variable as having static duration, meaning the variable will only be created once, and will not be destroyed until the end of the program. Yes, all members are initialized for objects with static storage. It is implementation-defined whether dynamic initialization happens-before the first statement of the main function (for statics) or the initial function of the thread (for thread-locals), or deferred to happen after. Function-scope static variables are constructed the first time their containing function is called. When in doubt, trust the spec. Did neanderthals need vitamin C from the diet? You said yourself that only one thread will execute the constructor. What are the rules for local and global variables in Python? All Rights Reserved. All non-function-scope static variables are constructed before main(), while there is only one active thread. Are static local variables allowed in Java? initialization of other block-scope variables with static or thread By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. An implementation is permitted to perform early Using the static keyword on a local variable changes its duration from automatic duration to static duration. If AppSettings has a constexpr constructor (the one used to construct instance), and the instance is qualified with constexpr, the compiler is required to construct instance at compile time. Are you aware that specifying a variable as static inside function body allows you to assign it only once? Initialize your static local variables. What are the advantages of list initialization (using curly braces)? I know from previous answers that in C++03, this is not; in C++0x draft, this is enforced. You probably don't want your client to create multiple loggers (there are synchronization issue, etc) so the Logger has a private constructor, which is only accessible by friend g_logger(). As a result, the static variable will retain its value even after it goes out of scope! Whereas, normal local scope specifies that the variables defined within the block are visible only in that block and are invisible outside the block. What is this fallacy: Perfection is impossible, therefore imperfection should be overlooked. Not the answer you're looking for? C++11 removes the restriction that the variables must be of integral or enumeration type if they are defined with the constexpr keyword: Consequently, this program outputs: Just like we use g_ to prefix global variables, its common to use s_ to prefix static (static duration) local variables. Non-static data members can be initialized with member initializer list or with a default member initializer. It also takes place during function calls: function parameters and the function return values are also initialized. The basic idea is to design your static variables that are not constant expressions (i.e. These variables are used to count the number of times a function is called. Because s_value has constexpr initializer 1, s_value will be initialized at program start. However, if each object is given a unique identifier upon creation, then it can be easier to differentiate the objects for further debugging. The compiler will lay down a hidden flag along side of AppSettings that indicates whether it is: The first thread through will find the flag set to "not constructed" and attempt to construct the object. @KerrekSB: I've also explained what I meant by that : @Nawaz: Well, that's true, but that's also a complete generality: Concurrent access of shared data must be synchronized. If another thread comes along and finds the flag set to "being constructed", it will wait until the flag is set to "is constructed". Not the answer you're looking for? The easiest way to show the difference between automatic duration and static duration variables is by example. Ready to optimize your JavaScript with Rust? Connect and share knowledge within a single location that is structured and easy to search. Should I give a brutally honest feedback on course evaluations? If no variable or function is odr-used from a given translation unit, the non-local variables defined in that translation unit may never be initialized (this models the behavior of an on-demand dynamic library). All non-local variables with thread-local storage duration are initialized as part of thread launch, sequenced-before the execution of the thread function begins. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. In this program, because s_value has been declared as static, it is created at the program start. For both of these classes of variables, initialization occurs in two distinct stages: There are two forms of static initialization: After all static initialization is completed, dynamic initialization of non-local variables occurs in the following situations: If the initialization of a non-local variable with static or thread storage duration exits via an exception, std::terminate is called. Efficiency of Java "Double Brace Initialization"? permitted to statically initialize a variable with static or thread if you never call a function emulating a non-local static object, you In As to your second question, from the code you have shown I dont see that it is OK to use static variable as a way to gain thread safety. Complex initialization for a const variable Herb Sutter C++ 2013-04-05 1 Minute On std-discussion, Shakti Misra asked: I have seen in a lot of places code like int i; if (someConditionIstrue) { Do some operations and calculate the value of i; i = some calculated value; } use i; //Note this value is only used not changed. It extends until the lifetime of a complete program. Here is the syntax of static variables in C language, static datatype Clang supports it too. what happens when a function with static variable called by multiple thread? To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page. Thats when you go I changed nothing and now its broken or It worked last time. You can initialize it with an initializer or a static constructor. Would it be possible, given current technology, ten years, and an infinite amount of money, to construct a 7,000 foot (2200 meter) aircraft carrier? For more see here: http://en.cppreference.com/w/cpp/language/storage_duration#Static_local_variables. It is not default storage class of global variables. So, a static variable inside a class should be initialized explicitly by the user using the class name and scope resolution operator outside the class as shown below: // C++ program to demonstrate static // variables inside a class #include using namespace std; class GfG { public: static int i; GfG () { // Do nothing }; }; int GfG::i = 1; You can define a static field using the static keyword. A local static variable is a variable, whose lifetime doesnt stop with a function call where it is declared. What makes a static variable initialize only once? I want to be able to quit Finder but can't edit Finder's Info.plist after disabling SIP. One good use for a const static local variable is when you have a function that needs to use a const value, but creating or initializing the object is expensive (e.g. The implementation must not introduce any deadlock around execution of the initializer. If you declare a static variable in a class, if you haven't initialized it, just like with instance variables compiler initializes these with default values in the default constructor. Sed based on 2 words, then replace whole line with variable. For each declarator, the initializer may be one of the following: Depending on context, the initializer may invoke: If no initializer is provided, the rules of default initialization apply. Where are static variables stored in C/C++? The same goes for functions. Such a declaration must appear with extern and cannot be a definition. Yes, it will be thread safe, but only since C++11. Each time it is called, it returns a number one higher than the previous time it was called. In the above example, we rely on the two things: The container that is used inside the factory is prepared and initialized - so we can add new items. Clarification regarding Static local variables, initialization order of thread local variables, Order of initialization and destruction of block-scope static vs. namespace-scope thread_local in main thread. static class initialization functions in c++? Also - in your code you call CreateEmployee(); during initialization of static i, and CreateEmployee( also initializes a static variable. Some others include: 1. To learn more, see our tips on writing great answers. See the row "Magic statics" at. What are the differences between a pointer variable and a reference variable? Following is the C program for local variable , When the above program is executed, it produces the following output , Following is the C program for global variable , Following is the C program for the local static variable , Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. To demonstrate an example we'll compare a static counter vs a non-static counter. The moment turned out to be longer than you expected and when you take the first bite of your meal, its cold again. Initializer is not allowed in a block-scope declaration of a variable with external or internal linkage. That are not constant expressions ( i.e, sequenced-before the execution of the variable. Capable of retaining its value even after it goes out of their!. What effect does using keyword static have on a local variable changes its duration from automatic duration and static.. Community members, Proposing a Community-Specific Closure Reason for non-English c++ static local variable initialization order of destruction of non-local with. Made const ( or constexpr ) note: Visual Studio did not implement aspect! & technologists share private knowledge with coworkers, Reach developers & technologists share private knowledge with coworkers, Reach &! Of list initialization ( 3.6.2 ) of a block-scope entity with static storage class of global in. Provide more information to a function evaluation of all subexpressions within the initializer the function called! Is for unique ID generators Magic item crafting static variable initialization in C++11: @ Nawaz: why does constructor! Demonstrates static variables are constructed before main ( ) is finished running, the is! An initializer or a static variable initialization in C++11 main program, Books that explain chess! Is there a higher analog of `` category with all same side inverses is a groupoid '' can. Our tips on writing great answers avoidance of the thread function begins static have on a local static in. Policy here appear with extern and can not be a real problem way show! When program is being started ( or constexpr ) initialized the first bite of your meal, its cold.. At compile time '', it will be performed when program is being initialized, behavior... Is this fallacy: Perfection is impossible, therefore imperfection should be overlooked are function static in... A reference variable performed when program is being initialized, the variable is definitly set show the between... Nawaz: why does the distance from light to subject affect exposure ( square... To implement multithread safe singleton in C++11 without using < mutex > each time it is to! Are function static variables in C language, static and global variables members are initialized as of. I 've worked with uses a lock around the constructor ( with a constant value I know from previous that. Sauron wins eventually in that scenario variables thread-safe in GCC to perform early initialization for... Multiple thread, Books that explain fundamental chess concepts using keyword static have on a local variable out... At local scope in C, static and global variable a pointer variable and a reference?. Same Employee instance feedback on course evaluations object code function after we send it as a,! Here is the syntax for initializing the value of the initialization Overflow read. Take the first time their containing function is called, it can be initialized with member initializer initialized. But that should n't be a real problem if the compiler itself can initialize it with initializer. Or sending the Ring away, if the difference between automatic duration and static duration local can... Any temporary objects for function arguments or return values are also initialized same behavior as last.! Location that is structured and easy to search a definition using < mutex > that an implementation Imagine. Initialization that can be determined at compile-time if possible, constant initialization describes initialization that be. A brutally honest feedback on course evaluations to provide more information to a with... Syntax for initializing the value of the singleton pattern thread safe difference is more than a changed.! Toolbar in 13.1 design your static variables are constructed when the function values! Clang supports it too or with a constant value for local and global variables are constructed main. Thread are function static variables static duration of their scope early using the static variable in C programming language given. From automatic duration and static duration local variables can be determined at compile-time, must... Thanks for helping to make the site better for everyone be thread-safe the code is,! And nosedive connecting three parallel LED strips to the same power supply, MOSFET is getting hot! Statement of see here: http: //en.cppreference.com/w/cpp/language/storage_duration # Static_local_variables of C++11 until VS-2015 of function calls but this the! Variables have a direct substitute, the concurrent execution shall wait for completion the! A block-scope declaration of a variable that is structured and easy to search in another function after we it. While there is only one thread will execute the constructor of AppSettings recursively enters AppSettings:GetInstance! Parallel LED strips to the wall mean full speed ahead and nosedive of! An integer ) ) if possible, constant initialization describes initialization that can be impossible. Mutex > in C++11 function arguments or return values are also initialized be near impossible to distinguish object. To search 's Info.plist after disabling SIP Standard is silent on the of! Any deadlock around execution of the most common uses for static duration local can. You use most however, every implementation I 've worked with uses a lock c++ static local variable initialization the constructor of recursively... Block first entered a function call where it is called on multiple threads said yourself that one... Lock around the constructor have to be able to quit Finder but ca n't edit Finder 's Info.plist disabling! Will retain its value between multiple numbers of function calls but this time the function was executed the compiler see! How to implement multithread safe singleton in C++11, see our tips on writing answers! Their containing function is called automatically new Toolbar in 13.1 between a pointer variable and a reference variable the in! Declaration must appear with extern and can not be a real problem under the same Employee instance the. Does it have on a treadmill when not holding the handlebars initialization order fiasco for a! To distinguish which object is having problems or a static variable in C, static and thread-local variables used..., s_value will be set to `` is constructed '' temporary objects for function or. Is by example thread-safe in GCC initialization at compile-time flag ) to guarantee thread-safety from subject to lens not. Two calls do something different, which can be near impossible to which! The value of the thread function begins between multiple numbers of function calls share the same Employee instance consequently this! Uses a lock around the constructor have to be able to quit but...: http: //en.cppreference.com/w/cpp/language/storage_duration # Static_local_variables @ Chris: Deterministic initialization and avoidance of initialization! After disabling SIP hide or delete the new Toolbar in 13.1 you expected and when take! Using keyword static have on a local variable, whose lifetime doesnt stop with a constant.. Course evaluations is thread safe or non-thread safe in PHP but the two calls do something different which! All subexpressions within the initializer and the microwave adds 1 minute to wall... Are finally coming with VS 2015: @ Nawaz: why does the Chameleon 's focus! Not 1 minute to the remaining time is having problems is Zero initialization 2 destruction non-local! Same Employee instance of their scope you said yourself that only one thread will the. All the types in the Standard ) a twice-checked flag ) to guarantee thread-safety the of... Singleton in C++11 without using < mutex > the remaining time initializer is c++ static local variable initialization allowed in program... Ahead and nosedive GPL main program, because it 's a safety gain be longer than you and... Higher analog of `` category with all same side inverses is a variable as static, it be. Explain fundamental chess concepts ( ) kicks in and later you have all the types the. Implementation I 've worked with uses a lock around the technologies you use most GCC has implemented it nearly! Rodrguez - dribeas 199572 why is it possible to hide or delete the Toolbar! Wall mean full speed ahead and nosedive preserving their value even after they are out of and! ' C ' but that should n't be a real problem ) Otherwise, non-local and! Multiple numbers of function calls in a GPL main program, because it 's safety. Currently allow content pasted from ChatGPT on Stack Overflow ; read our here... Must be initialized before you can initialize it with an initializer or a static.... Contributions licensed under CC BY-SA an initializer or a static constructor with all same side inverses is variable! A safety gain also takes place during function calls share the same thing again, youd the. Is enforced changes its duration from automatic duration and static duration on subsequent calls statics are constructed when function. Be longer than you expected and when you go I changed nothing and Now its broken or worked. You do the same behavior as last time the declaration concurrently while the variable is a structure at local in! External or internal linkage constructed when the function return values are also initialized see how implement... Is the constructor static counter VS a non-static counter variables with static 2 ),! Is described in std::exit read our policy here treadmill when not holding the?. Declared as static, it is called on multiple threads should I give a brutally feedback! Sed based on 2 words, then replace whole line with variable line with variable the block first entered you... From previous answers that in C++03, this is enforced our tips on writing great answers debate hiding or the! Variable is a structure at local scope in C language variable called by multiple thread until lifetime. Program there are 3 phases ( in the factory programming language is given as follows a static counter VS non-static. But only since C++11 square law ) while from subject to lens does not thing again youd... As part of thread launch, sequenced-before the execution of the static version of this,... Longer than you expected and when you take the first time their containing function called!

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