C++ Tutorial Index

C++ Tutorial C++ History C++ Installation C++ First Program C++ cin and cout C++ Data type C++ Variable C++ operator C++ Keywords

C++ Control Statements

C++ If C++ Nested if C++ If-else C++ If-else-if C++ Switch C++ Break C++ Continue C++ Goto C++ For loop C++ While loop C++ Do while loop

C++ Functions

C++ Call by Value C++ Call by Reference C++ Recursion Function C++ Inline function C++ Friend function

C++ Arrays

Single dimension array Two dimension array

C++ Strings

C++ Strings

C++ Inheritance

C++ Inheritance Single level Inheritance Multilevel Inheritance Multiple Inheritance Hierarchical Inheritance Hybrid Inheritance

C++ Polymorphism

C++ Polymorphism C++ Overloading C++ Overriding C++ Virtual Function

C++ Pointers

C++ Pointers C++ this pointer

C++ Exception Handling

C++ Exception Handling

C++ Constructors

C++ Constructors Default Constructor Parameterize Constructor Copy constructor Constructor Overloading Destructor

C++ File Handling

C++ File Handling C++ Writing to file C++ Reading file C++ Close file

Miscellaneous

C Vs C++ C++ Comments C++ Data Abstraction C++ Identifier C++ Memory Management C++ Storage Classes C++ Void Pointer C++ Array To Function C++ Expressions C++ Features C++ Interfaces C++ Encapsulation std::min in C++ External merge sort in C++ Remove duplicates from sorted array in C++ Precision of floating point numbers Using these functions floor(), ceil(), trunc(), round() and setprecision() in C++ C++ References C++ Friend Functions C++ Mutable keyword Unary Operators in C++ Initialize Array of objects with parameterized constructors in C++ Differences between #define & const in C/C++ C++ Program to Implement Shell Sort C++ Program to Implement Merge Sort Storage Classes in C Vector resize() in C++ Passing by Reference Vs. Passing by the pointer in C++ Free vs delete() in C++ goto statement in C and C++ C++ program to read string using cin.getline() C++ String Concatenation Heap Sort in C++ Swap numbers in C++ Input Iterators in C++ Fibonacci Series in C++ C ++ Program: Alphabet Triangle and Number Triangle C++ Program: Matrix Multiplication C++ Program to Print Fibonacci Triangle Stack in C++ Maps in C++ Queue in C++ C++ Bitset C++ Algorithms Priority Queue in C++ C++ Multimap C++ Deque Function Pointer in C++ Sizeof() Operators in C++ C++ array of Pointers free() Vs delete in C Timsort Implementation Using C++ CPP Templates C++ Aggregation C++ Enumeration C++ Math Functions C++ Object Class C++ Queue Initialize Vector in C++ Vector in C++ C++ STL Components Function overloading in C++ C++ Maximum Index Problem C++ find missing in the second array C++ Program to find the product array puzzle C++ Program To Find Largest Subarray With 0 Sum C++ Program To Move All Zeros To The End Of The Array C++ Program to find the element that occurs once C++ Program to find the largest number formed from an array Constructor Vs Destructor C++ Namespaces C++ OOPs Concept C++ Static C++ Structs C++ Try-Catch C++ User Defined Exceptions C++ Virtual Destructor C++ vs C# Malloc() and new in C++ Palindrome Number Program in C++ Snake Code in C++ Splitting a string in C++ Structure Vs Class in C++ Virtual Function Vs Pure Virtual Function C++ Bidirectional Iterators C++ Forward Iterators C++ Iterators C++ Output Iterators C++ Range-based For Loop Converting string into integer in C++ LCM Program in C++ Type conversion in C++ Add two numbers using the function in C++ Advantage and disadvantage friend function C++ Armstrong Number Program in C++ ATM machine program in C++ using functions Binary to Decimal in C++ Bit Manipulation in C++ C++ Constructor C++ Dijkstra Algorithm Using the Priority Queue C++ int into String C++ Signal Handling Decimal to Binary in C++ Decimal to Hexadecimal in C++ Decimal to Octal in C++ Factorial Program in C++ Function in C++ Hexadecimal to Decimal in C++ Octal to Decimal in C++ Reverse a Number in C++ Structure Vs Class in C++ C++ Forward Iterators C++ Output Iterators C++ Prime number program Char Array to String in C++ Constructor Overloading in C++ Default arguments in C++ Different Ways to Compare Strings in C++ Dynamic Binding in C++ Program to convert infix to postfix expression in C++ SET Data Structure in C++ Upcasting and Downcasting in C++ Reverse an Array in C++ Fast Input and Output in C++ Delete Operator in C++ Copy elision in C++ C++ Date and Time C++ Bitwise XOR Operator Array of sets in C++ Binary Operator Overloading in C++ Binary Search in C++ Implementing the sets without C++ STL containers Scope Resolution Operator in C++ Smart pointers in C++ Types of polymorphism in C++ Exception Handling in C++ vs Java Const Keyword in C++ Type Casting in C++ Static keyword in C++ vs Java Inheritance in C++ vs Java How to concatenate two strings in C++ Programs to Print Pyramid Patterns in C++ swap() function in C++ Structure of C++ Program Stringstream in C++ and its applications rand() and srand() in C / C++ C++ Ternary Operator C++ Scope of Variables While Loop Examples in C++ Star pattern in C++ using For Loops For Loop Examples in C++ Do-While Loop Examples in C++ Top 5 IDEs for C++ That You Should Try Once Assertions in C/C++ C++ Convert Int to String Continue in C++ While loop Diamond Pattern in C++ using For Loop How to Reverse a String in C++ using Do-While Loop How to Reverse a String in C++ using For Loop How to Reverse a String in C++ using While Loop Infinite loop in C++ Loops in C++ Returning Multiple Values from a Function using Tuple and Pair in C++ wcscpy(), wcslen(), wcscmp() Functions in C++

C++ Signal Handling

Signals are interruptions sent by the operating system to a process to cause it to cease doing its current job and focus on the task for which the interrupt was produced. The operating system can also emit signals based on system or error conditions.

There are some signals that the program will not detect, however there is a list below of signals that you may catch in your program and use to take necessary actions.

The following is a list of signals, along with their descriptions and capabilities:

SIGABRTAbnormal program termination, such as a request to abort.
SIGFPEA mistaken arithmetic operation, such as a division by zero or an overflow operation.
SIGILLIt is used to identify erroneous instructions.
SIGINTIt receives an interrupt signal from an interactive program.
SIGSEGVIncorrect storage access.
SIGTERM        A program termination request was issued.
SIGHUPIt reports that the user's terminal is disconnected (POSIX). It is used to indicate that the controlling procedure has ended.
SIGQUITTo end a process and create a core dump, use this command.
SIGTRAPTrap for traces.
SIGBUSThis is a BUS error, indicating that you tried to visit an incorrect address.
SIGUSR1Signal 1 is a user-defined signal.
SIGUSR2Signal 2 is a user-defined signal.
SIGALRMAccess to an incorrect address is shown by an alarm clock.
SIGTERMTermination device.
SIGCOUNTThis signal can be ignored, blocked, or handled.
SIGSTOPThis signal delivered to process to make it proceed.

The function signal ()

Unexpected interruptions or events can be trapped using the signal-handling library's function signal.

void (*signal (int sig, void (*func)(int)))(int);  //syntax

Parameters:

  • The signal is handled by this function.
  • It describes how to handle the number of signals indicated by sig.

The parameter func defines one of the three methods a programme can handle a signal.

  • SIG DFL (default handling): The signal that is handled by the default action for that signal.
  • Ignore Signal (SIG IGN): The signal is ignored, and the code execution continues even if the signal was not intended.
  • Specific function is defined to handle the signal.
  • It is important to remember that the signal we want to capture should be recorded with the signal function and connected with the signal handling function.

Note: The signal processing function should be of type void.

Return

This function's return type is the same as the type of its parameter func. If this method's request is successful, it provides a reference to the handler function that was in responsibility of processing this signal before the call, if one existed.

Data Races

The term "data race" is undefined. If you call this function in a multi threading software then it will create undefined behavior.

Example to show how to utilize the signal() function:

#include <iostream> 
#Include <bits/sdtc++.h>
#include <stdlib>
#include <csignal>  
using namespace std;  
signal signalled = 0;  
void handler(int signal)  
{  
    signalled = 1;  
}  
int main()  
{  
    sig(SIGINT, handler);  
    raise(SIGINT);  
    if (signalled)  
        cout << "Signal is handled";  
    else  
        cout << "Signal is not handled";  
    return 0;  
}  

OUTPUT:

Signal is handled

Explanation

In the above example in C++, we used data races which is undefined which calls the function in multi threading software.

Another example to show how to utilize the signal() function:

#include <csignal>  
#include <iostream> 
#include <bits/sdtc++.h> 
#include <stdlib>
using namespace  
{  
  volatile std::sig eSignal_Status;  
}  
void signal_handler(int signal)  
{  
  eSignal_Status = signal;  
}  
int main()  
{  
  // Install a signal handler  
  std::signal(SIGINT, signal_handler);  
  std::cout << "Signal_Value: " << eSignal_Status << '\n';  
  std::cout << "Sending_signal " << SIGINT << '\n';  
  std::raise(SIGINT);  
  std::cout << "Signal_Value: " << eSignal_Status << '\n';  
}  

OUTPUT:

Signal_Value: 0
Sending_signal 2
Signal_Value: 2

Explanation

In the above example in C++, we have utilized the signal function which calls the function in multi threading software.

The function race ()

Signals are sent to the currently running application using the C++ signal raise () method.

The raise () method was declared in the < csignal > header file to handle a specific signal.

int raise (int signal);  //syntax

The signal number that should be forwarded for processing. One of the following values can be used:

  • SIGINT
  • SIGABRT
  • SIGFPe
  • SIGILL
  • SIGSeGV
  • SIGTeRM
  • SIGHUP

Return Value

On success, it returns 0; on failure, it returns a non-zero.

Exception

If no function handlers have been specified with signal to handle the raised signal, this function never throws an exception.

Example of a program showing how to utilize the raise () method when SIGABRT is passed:

#include <iostream>
#inlcude <bits/stdc++.h>
#include <stdlib>  
#include <csignal>  
using namespace std;  
signal sig_value = 0;  
void handler(int sig)  
{  
    sig_value = sig;  
}  
int main()  
{  
    signal(SIGABRT, handler);  
    cout << "Before signal handler is called" << endl;  
    cout << "Signal = " << sig_value << endl;   
    raise(SIGABRT);  
    cout << "After signal handler is called" << endl;  
    cout << "Signal = " << sig_value << endl;  
    return 0;  
}  

OUTPUT:

Before signal handler is called
Signal = 0
After signal handler is called
Signal = 6

Explanation

In the above program in C++, we have passed SIGABRT and utilized the raise function by passing SIGABRT and handler in the main function.



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