Tutorialspoint.dev

Concept of setjump and longjump in C

“Setjump” and “Longjump” are defined in setjmp.h, a header file in C standard library.

  • setjump(jmp_buf buf) : uses buf to remember current position and returns 0.
  • longjump(jmp_buf buf, i) : Go back to place buf is pointing to and return i .
// A simple C program to demonstrate working of setjmp() and longjmp()
#include<stdio.h>
#include<setjmp.h>
jmp_buf buf;
void func()
{
    printf("Welcome to GeeksforGeeks ");
  
    // Jump to the point setup by setjmp
    longjmp(buf, 1);
  
    printf("Geek2 ");
}
  
int main()
{
    // Setup jump position using buf and return 0
    if (setjmp(buf))
        printf("Geek3 ");
    else
    {
        printf("Geek4 ");
        func();
    }
    return 0;
}

Output :

Geek4
Welcome to GeeksforGeeks
Geek3

The main feature of these function is to provide a way that deviates from standard call and return sequence. This is mainly used to implement exception handling in C. setjmp can be used like try (in languages like C++ and Java). The call to longjmp can be used like throw (Note that longjmp() transfers control to the point set by setjmp()).



This article is attributed to GeeksforGeeks.org

leave a comment

code

0 Comments

load comments

Subscribe to Our Newsletter