# Introduction

In C programming language, we use `goto` to jump to a specific location **within** the same function.
When we want to jump to a location that is in **another** function, we can use `setjump` and `longjump` to accomplish that.

The basic idea of is that, we use `setjump` function to mark the place we want to jump to, and use `longjump` function to jump. Here is a simple example:

# Example

#include <setjmp.h>
#include <stdio.h>

jmp_buf buf;

void foo()
{
    printf("foo: begin\n");

    /* Jump to bar */
    longjmp(buf, 0);

    /* Won't reach here */
    printf("foo: end\n");
}

void bar()
{
    printf("bar: begin\n");
    
    /* Set jmp_buf to jump here */
    if (setjmp(buf) == 0)
        return;
    printf("bar: end\n");
}

int main(int argc, char *argv[])
{
    bar();
    foo();
    return 0;
}

Compile and run:

$ gcc setjmp.c -o setjmp
$ ./setjmp
bar: begin
foo: begin
bar: end