longjmp (C++)

Was introduced to this keyword through CS343.

DME is possible in C using:

• jmp_buf to declare a label variable,
• setjmp to initialize a label variable,
• longjmp to goto a label variable.

https://www.fmc-modeling.org/category/projects/apache/amp/A_5_Longjmp.html

Resources

• https://stackoverflow.com/questions/14685406/practical-usage-of-setjmp-and-longjmp-in-c
• https://stackoverflow.com/questions/32752204/save-copy-jmp-buf-c

what happens if i call longjmp(jumpbufer, 2)? That sets the value of jmpBuffer to 2? so then, setjmp(jumpBuffer) == 2) is true?

• Yes

#include <iostream>
#include <csetjmp>
 
jmp_buf jumpBuffer;
 
void someFunction() {
    std::cout << "In some function. Triggering longjmp...\n";
    longjmp(jumpBuffer, 2);  // This makes setjmp return 2
}
 
int main() {
    int val = setjmp(jumpBuffer);
 
    if (val == 0) {
        std::cout << "Setjmp returned 0, normal execution.\n";
        someFunction();  // Call the function that will trigger longjmp
    } else if (val == 2) {
        std::cout << "Setjmp returned 2 after longjmp.\n";
    }
 
    std::cout << "Program continues...\n";
    return 0;
}