What is the difference between throwing an exception and performing an abort operation in a program?

Differences between throwing an exception and aborting a program

Throwing an exception and aborting a program are two different mechanisms for handling undesirable or erroneous situations in a C/C++ program.

The main difference lies in their purpose, response method, and impact on program execution.

Characteristic	Throwing an exception (throw exception)	Program abort (abort())
Purpose	Notification of an unusual but potentially manageable situation. Recovery of execution is possible.	Immediate termination of the program in case of a critical error. Continuation is not expected.
Mechanism	Use of keywords throw, try, catch. Stack unwinding occurs.	Call of the abort() function from the standard library. Immediately terminates execution.
Stack unwinding	Happens: local objects are automatically destroyed with destructor calls.	Does not happen: local object destructors are not called.
Handling	Expected to be caught by a catch block. Error handling and continuation of execution are possible.	Not expected: the program terminates.
Signal	Does not generate a standard operating system signal.	Generates a standard signal (usually SIGABRT).
OS notification	Does not directly notify the OS of a fatal error.	Notifies the OS of a fatal error, which may lead to a memory dump.

Throwing an exception

When an exception is thrown, the program enters a search mode for a handler that can "catch" this exception. If such a handler is found, control is transferred to it, allowing recovery or error processing logic to be executed. Stack unwinding occurs automatically, guaranteeing the call of local destructors, which helps prevent resource leaks.

#include <iostream>
#include <stdexcept>

void might_throw() {
    throw std::runtime_error("Something went wrong"); // Throw an exception
}

int main() {
    try {
        might_throw();
    } catch (const std::runtime_error& e) { // Catch the exception
        std::cerr << "Caught exception: " << e.what() << std::endl;
        // Ability to continue execution
    }
    return 0;
}

Program abort

Aborting a program, triggered by the abort() function, leads to immediate and forced termination of execution. This mechanism is used to indicate critical, unhandled errors when continuing program operation is unsafe or impossible. Stack unwinding does not occur, and local destructors are not called. This can lead to resource leaks if the program relies on destructors for cleanup.

#include <iostream>
#include <cstdlib> // For abort()

void critical_error() {
    std::cerr << "Critical error encountered. Aborting!" << std::endl;
    std::abort(); // Calls abort
}

int main() {
    critical_error();
    // This line will never be reached
    return 0;
}

Overall, exceptions are used for handling errors that can be foreseen and potentially corrected, while abort indicates a fatal error requiring immediate termination.