_Generic - Linux
Overview
The _Generic
keyword is used in C++ to provide generic programming capabilities, allowing functions and classes to be defined in a way that works for a variety of data types. It allows the compiler to select the appropriate implementation based on the type of the arguments passed to the function or class.
Syntax
_Generic((expression), (type-1): (expression-1), ..., (type-n): (expression-n))
Where:
- expression is the expression to be evaluated.
- type-i is the type of the argument(s) for expression-i.
- expression-i is the expression to be evaluated if the argument(s) have the type type-i.
Options/Flags
N/A
Examples
// Generic function to calculate the area of a shape
double calculateArea(_Generic(shape,
circle: (3.14 * pow(shape.radius, 2)),
rectangle: (shape.width * shape.height),
triangle: (0.5 * shape.base * shape.height)))
// Generic class for a container
template<_Generic(T, vector: std::vector<T>, list: std::list<T>)>
class Container {
public:
void add(T element) { ... }
T get(int index) { ... }
int size() { ... }
};
Common Issues
- Compiler errors: If the compiler cannot determine the type of the arguments passed to the generic function or class, it will result in a compiler error. Ensure the argument types match the specified types in the
_Generic
expression. - Code bloat: Using
_Generic
can lead to code bloat if there are many different types of arguments. Consider using templates or virtual functions as alternatives.
Integration
_Generic
can be integrated with other C++ features such as:
- Templates: Generic functions and classes can be used within templates.
- Inheritance: Derived classes can inherit generic functions and classes from base classes.
- Overloading: Generic functions can be overloaded for different types of arguments.
Related Commands
std::enable_if
std::is_same
std::conditional