In the C programming language, an external variable is a variable defined outside any function block. On the other hand, a local (automatic) variable is a variable defined inside a function block. As an alternative to automatic variables, it is possible to define variables that are external to all functions, that is, variables that can be accessed by name by any function. (This mechanism is rather like Fortran COMMON or Pascal variables declared in the outermost block.) Because external variables are globally accessible, they can be used instead of argument lists to communicate data between functions. Furthermore, because external variables remain in existence permanently, rather than appearing and disappearing as functions are called and exited, they retain their values even after the fun
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| rdfs:label
| - Variable externa (ca)
- Variable externa (es)
- External variable (en)
- 外部变量 (zh)
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| - Una variable externa és, en els llenguatges de programació C i C++, una variable declarada amb la <b>extern</b>. (ca)
- Una variable externa es, en los lenguajes de programación C y C++, una variable declarada con la palabra clave extern. (es)
- 在B语言、C语言和一些其它派生的语言（如C++）中，外部变量即外部的变量。这并不是语言规范中直接明确的概念，因此含义可能有歧义。严格地，“外部”可以指变量名具有的外部链接(external linkage)，据此外部变量指变量名具有外部链接的变量。其它理解导致外延与之具有一定差异，在下面的例子中注释。 注意“变量”的概念在这些语言中本身即具有一些差异。ISO C中没有作为名词的“变量”(variable)这一术语的正式定义，通常即指对象，而ISO C++规定变量通过对象或不是非静态数据成员的引用的声明引入，其中“对象”的概念和ISO C的基本兼容。除非另行说明，下文取其公共含义，即变量均指对象。变量名在此即为标识符（C++的名称外延比标识符更广，在此不考虑非标识符的情形）。 (zh)
- In the C programming language, an external variable is a variable defined outside any function block. On the other hand, a local (automatic) variable is a variable defined inside a function block. As an alternative to automatic variables, it is possible to define variables that are external to all functions, that is, variables that can be accessed by name by any function. (This mechanism is rather like Fortran COMMON or Pascal variables declared in the outermost block.) Because external variables are globally accessible, they can be used instead of argument lists to communicate data between functions. Furthermore, because external variables remain in existence permanently, rather than appearing and disappearing as functions are called and exited, they retain their values even after the fun (en)
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| - Una variable externa és, en els llenguatges de programació C i C++, una variable declarada amb la <b>extern</b>. (ca)
- In the C programming language, an external variable is a variable defined outside any function block. On the other hand, a local (automatic) variable is a variable defined inside a function block. As an alternative to automatic variables, it is possible to define variables that are external to all functions, that is, variables that can be accessed by name by any function. (This mechanism is rather like Fortran COMMON or Pascal variables declared in the outermost block.) Because external variables are globally accessible, they can be used instead of argument lists to communicate data between functions. Furthermore, because external variables remain in existence permanently, rather than appearing and disappearing as functions are called and exited, they retain their values even after the functions that set them have returned. — The C Programming Language (en)
- Una variable externa es, en los lenguajes de programación C y C++, una variable declarada con la palabra clave extern. (es)
- 在B语言、C语言和一些其它派生的语言（如C++）中，外部变量即外部的变量。这并不是语言规范中直接明确的概念，因此含义可能有歧义。严格地，“外部”可以指变量名具有的外部链接(external linkage)，据此外部变量指变量名具有外部链接的变量。其它理解导致外延与之具有一定差异，在下面的例子中注释。 注意“变量”的概念在这些语言中本身即具有一些差异。ISO C中没有作为名词的“变量”(variable)这一术语的正式定义，通常即指对象，而ISO C++规定变量通过对象或不是非静态数据成员的引用的声明引入，其中“对象”的概念和ISO C的基本兼容。除非另行说明，下文取其公共含义，即变量均指对象。变量名在此即为标识符（C++的名称外延比标识符更广，在此不考虑非标识符的情形）。 (zh)
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