How are static functions different from global functions

Macros are dangerous because their use resembles that of real functions, but they have different semantics. The inline function-specifier was introduced to the C programming language in the C99 standard. Inline functions should be preferred over macros when they can be used interchangeably. Making a function an inline function suggests that calls to the function be as fast as possible by using, for example, an alternative to the usual function call mechanism, such as inline substitution. (See also Inline substitution is not textual substitution, nor does it create a new function. For example, the expansion of a macro used within the body of the function uses the definition it had at the point the function body appeared, not where the function is called; and identifiers refer to the declarations in scope where the body occurs. Arguably, a decision to inline a function is a low-level optimization detail that the compiler should make without programmer input. The use of inline functions should be evaluated on the basis of (a) how well they are supported by targeted compilers, (b) what (if any) impact they have on the performance characteristics of your system, and (c) portability concerns. Static functions are often as good as inline functions and are supported in C. Noncompliant Code Example In this noncompliant code example, the macro CUBE() has inline int cube(int i) Noncompliant Code Example In this noncompliant code example, the programmer has written a macro called EXE...

I need to have method to get something from a database, but I don't understand the difference between static and normal functions in PHP. Example code class Item If I use $item = Item::getDetail(15); and $item = getDetail(15); — they're the same. • What is the difference between static and function outside of a class? • If they are difference, How to use static function and function outside of a class? (I'd appreciate a really simple example.) • What are the performance properties between static and function outside of a class? Which is better? 1) What is difference between static function and normal function While they are functions, I'd prefer to call them methods of a given class. One is a static method and the other is an instance method. Static Method: $item = Item::getDetail(15); Instance Method: $item = getDetail(15); (refer to FuzzyTree's correct syntax above in the comments, however.) 2) How to use static function and normal function (if you simple exemplify is good) Static means you do not have to instantiate (declare an object reference). That is, you can simply use the method. So, in your example, while the answer may be the same, the way you called that method/function is different, as you noted above. In Java, for example, you have the Math class. It does not require instantiation to use, and in fact you cannot that I know of because its constructor is private. You can simply use a method by referencing the class and the method name you wish to use, Math.pow...

@MatthieuM.: Actually the presence of 'private member' is exactly what lead me to believe that he does mean static functions in the C++ sense. Because file-scoped static functions and private member functions are the two things that have very similar use in C++, while replacing public static member with private non-static member just does not make much sense. Unfortunately OP does not seem to be responding. Assuming that you're using Other than the above, I find static functions useful when you don't want to create an instance of an object just to execute one public function on it. This is mainly the case for helper classes that contain public functions to do some repetitive and general work, but don't need to maintain any state between calls. Because they don't require an instance and can be public. Say you need a function to get the greatest common denominator (GCD; very useful for fraction classes; and yes this is just a simple example). There is no point in creating a class of objects whose sole purpose is that you can have a this pointer you neither need nor use in gcd. So you use a static method for it, ideally on the class which actually uses the GCD (e.g. in the fraction class). Of coures if there are only static methods, you're doing OOP wrong and should either switch to actually doing OOP or using a language more appropriate to your paradigm. Okay, thanks for the reassurance. I only learned this best practice recently. However, then I'm at the moment having troub...

Does a blue car have two doors or four doors? The two characteristics are unrelated. static is a well defined term that hat refers to storage class (the life of the variable). Global is a popular intuitive term that is frequently used to describe the scope of a variable (where it is visible). The correct term is file scope. A static variable CAN have file scope. It can also have other scopes. It depends on how and where it is declared.

In C# I have a library of often used functions which I link to for each new app to avoid re-inventing the wheel. I am starting to build up something similar in D7 but I am running into what I think is a terminology problem. In C# all the functions are declared as 'static' so I can call them with the library name e.e. JGLib.JWriteLog(..); In D7 'static' seems to mean something different as trying to use it as a modifier throws up compiler errors. What I do is to set up a global instance of the library and use: m_JGLib.JWriteLog(..); Can I avoid this by adding a modifier to a function declaration or is this the way to do it in D7? Many thanks. -- Jeff Gaines - Damerham Hampshire UK Posted with XanaNews 1.16.4.6 http://www.wilsonc.demon.co.uk/d7xananews.htm Quote Jeff Gaines wrote: > In C# all the functions are declared as 'static' so I can call them > with the library name e.e. In Object Pascal these are called "class methods". Silly example : type TStaticClass = class public class function DoubleMe(aParam: integer): integer; end; implementation class function TStaticClass.DoubleMe(aParam: integer): integer; begin Result := aParam + aParam; end; You can then write x := TStaticClas.DoubleMe(2); Danny --- Quote > Jeff Gaines wrote: >> In C# all the functions are declared as 'static' so I can call them >> with the library name e.e. > In Object Pascal these are called "class methods". Silly example : > type >TStaticClass = class >public >class function DoubleMe(aParam: integer)...

Unlike global functions in C, access to static functions is restricted to the file where they are declared. Therefore, when we want to restrict access to functions, we make them static. Another reason for making functions static can be reuse of the same function name in other files. For example, if we store following program in one file file1.c Now, if we compile the above code with command “ gcc file2.c file1.c”, we get the error “undefined reference to `fun1’” . This is because fun1() is declared static in file1.c and cannot be used in file2.c. Please write comments if you find anything incorrect in the above article, or want to share more information about static functions in C.

Almost every projects contains Utility Functions. With the introduction of Swift, there are multiple ways to write such functions. Static Functions Static functions are invoked by the class itself, not by an instance. This makes it simple to invoke utility functions without having to manage an object to do that work for you. class AppUtils We can just access them as appUtility() anywhere in the project. If you have method with same name as of global function, then access global function with MyAppName.appUtility() In case of static functions, if we access one of the static member, entire class gets loaded in memory. But in case of global function, only that particular function will be loaded in memory. So, which one is better to use? It is largly subjective why we pick one over another. Some prefer static method approach as a form of namespacing. For example, using the static method approach also allows us to have a method ClassA.appUtility() and a method named ClassB.appUtility(), which is useful while developing a library or framework. Global functions are more modular and factor out single tasks for a single function - a good global utility function that does exactly one thing and does it perfectly can also sometimes be abstracted or made generic and used in other context as well. We can just create a AppUtility.swift file and put all the utility functions in it. Later this file can be used across multiple projects.

Unlike global functions in C, access to static functions is restricted to the file where they are declared. Therefore, when we want to restrict access to functions, we make them static. Another reason for making functions static can be reuse of the same function name in other files. For example, if we store following program in one file file1.c Now, if we compile the above code with command “ gcc file2.c file1.c”, we get the error “undefined reference to `fun1’” . This is because fun1() is declared static in file1.c and cannot be used in file2.c. Please write comments if you find anything incorrect in the above article, or want to share more information about static functions in C.

In C# I have a library of often used functions which I link to for each new app to avoid re-inventing the wheel. I am starting to build up something similar in D7 but I am running into what I think is a terminology problem. In C# all the functions are declared as 'static' so I can call them with the library name e.e. JGLib.JWriteLog(..); In D7 'static' seems to mean something different as trying to use it as a modifier throws up compiler errors. What I do is to set up a global instance of the library and use: m_JGLib.JWriteLog(..); Can I avoid this by adding a modifier to a function declaration or is this the way to do it in D7? Many thanks. -- Jeff Gaines - Damerham Hampshire UK Posted with XanaNews 1.16.4.6 http://www.wilsonc.demon.co.uk/d7xananews.htm Quote Jeff Gaines wrote: > In C# all the functions are declared as 'static' so I can call them > with the library name e.e. In Object Pascal these are called "class methods". Silly example : type TStaticClass = class public class function DoubleMe(aParam: integer): integer; end; implementation class function TStaticClass.DoubleMe(aParam: integer): integer; begin Result := aParam + aParam; end; You can then write x := TStaticClas.DoubleMe(2); Danny --- Quote > Jeff Gaines wrote: >> In C# all the functions are declared as 'static' so I can call them >> with the library name e.e. > In Object Pascal these are called "class methods". Silly example : > type >TStaticClass = class >public >class function DoubleMe(aParam: integer)...

Almost every projects contains Utility Functions. With the introduction of Swift, there are multiple ways to write such functions. Static Functions Static functions are invoked by the class itself, not by an instance. This makes it simple to invoke utility functions without having to manage an object to do that work for you. class AppUtils We can just access them as appUtility() anywhere in the project. If you have method with same name as of global function, then access global function with MyAppName.appUtility() In case of static functions, if we access one of the static member, entire class gets loaded in memory. But in case of global function, only that particular function will be loaded in memory. So, which one is better to use? It is largly subjective why we pick one over another. Some prefer static method approach as a form of namespacing. For example, using the static method approach also allows us to have a method ClassA.appUtility() and a method named ClassB.appUtility(), which is useful while developing a library or framework. Global functions are more modular and factor out single tasks for a single function - a good global utility function that does exactly one thing and does it perfectly can also sometimes be abstracted or made generic and used in other context as well. We can just create a AppUtility.swift file and put all the utility functions in it. Later this file can be used across multiple projects.