How to speed up g++ during compile time

Fast compilation on g++ build systems is basically used in compiling and executing C++ programs in the terminal. There are many options to speed up the compilation or even slow it down. Some of them are as follows:

g++ {filename.cpp} -fconcepts:

• Compiling a program with fconcepts will not give any error as fconcepts ignores the warning.
• If the code is executed normally, it will give an error.
• In this way, fconcepts speed up the debugging.

Syntax:

g++ <filename.cpp> -fconcepts

Below is the C++ program to illustrate the use of -fconcepts:

C++

// C++ program to illustrate the use
// of -fconcepts
#include <bits/stdc++.h>
using namespace std;

// Function to print the integer a
void print(auto a)
{
    cout << a << endl;
}

// Driver Code
int main()
{
    int a = 5;

    // Function Call
    print(a);

    return 0;
}

Output:

Generally, functions do not allow an auto variable as function parameters. But using -fconcepts this error can be ignored.

g++ {filename.cpp} -Wall:

• Compiling the same code using -Wall will give warnings as it will not ignore it.
• It also prompts as to where the code is wrong.

Syntax:

g++ <filename.cpp> -Wall

Below is the C++ program to illustrate the use of -Wall:

C++

// C++ code to illustrate the use
// of -Wall
#include <iostream>
using namespace std;

// Function to print a
void print(auto a)
{
    cout << a << endl;
}

// Driver Code
int main()
{
    int a = 5;

    // Function call
    print(a);

    return 0;
}

Output: