How is function overloading implemented in C++ function templates?

In C function templates, function overloading can be achieved by compiler generation of different symbol names and code generation. The compiler performs matching based on the passed parameter types and selects the best matching overload. For example, print(T) and print(T, U) are defined in the template. When the actual call is made, the parameter types passed in are int and double. The compiler will generate the codes for print(int) and print(int, double), and based on The parameter matching algorithm selects the best matching overload.

The implementation principle of function overloading in C function template

In C, function template can represent a series of functions with the same function But functions called with arguments of different types. If there are multiple overloaded functions in the template, the compiler will select the best matching function based on the actual parameter types passed in.

The principle of implementing function template overloading is:

1. The compiler generates different symbol names

for each overloaded function template , the compiler will generate a different symbol name. This means that each overload is essentially a separate function, but they still inherit from the same template definition.

2. Code generation

When the compiler encounters a function template call, it will generate the code for a specific function based on the actual parameter types passed in. For example, if the following overload exists in the template:

template<typename T>
void print(T value);

Then for the following call, the compiler will generate code for the print(int) function:

print(42);

3. Parameter matching

The compiler uses a parameter matching algorithm to select the best matching overload. It compares the passed parameter types to the signature of each function template and selects the overload that most closely matches the parameters.

Practical case

The following code demonstrates the principle of function template overloading:

#include <iostream>

template<typename T>
void print(T value) {
    std::cout << "Value: " << value << std::endl;
}

template<typename T, typename U>
void print(T value1, U value2) {
    std::cout << "Value1: " << value1 << ", Value2: " << value2 << std::endl;
}

int main() {
    print(42);              // 调用 print(int)
    print(42, 3.14);         // 调用 print(int, double)

    return 0;
}

Result:

Value: 42
Value1: 42, Value2: 3.14

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