Creating a loop using setJmp longJmp

Question

I am trying to create an infinite loop using those functions (unsuccessfully).

My code :

jmp_buf buf1;

void foo(){
    int z = 4, y = 1;
    int v = setjmp(buf1);
    if(v == 0){
     printf("A%d", z);
     longJmp(buf1, 1);
    }
    else if(v == 1){
        printf("B%d", y);
        longjmp(buf1,1);
    }
}

int main(){
    int v = setjmp(buf1);
    if( v == 0){
        printf("C%d", 1);
        foo();
        longjump(buf1,1);
    }
}

I thought it would print C1A4B1B1B1.... (B1 repeats forever) but I just get C1A4B1 and the program stops (SEGMENTATION ERROR). Isn't calling longJmp always return to setJmp with parameter val?

Would like to understand where is my mistake.

EDIT : The code I copied before I got answers is mistakenly incorrect, longjmp(buf1,2) instead of longjmp(buf1,1). Also I didn't copy the full main code which cause the seg fault. (another longjmp after foo being called)

Answer 1

after line 15, longjmp(buf1,2);
v is 2.

When next repeat, v is not 1, function has end.

longjmp(buf1,2); > longjmp(buf1,1);