setjmp/longjmp and volatile

jmp.c

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

jmp_buf buf;
void jmper() {
    // only variables marked as volatile can be seen as reiable
    // written after jmp, as they are written to ram
    volatile int local = 1;
    if (!setjmp(buf)) {
        printf("pre set: %d\n", local);   // 1
        local = 2;
        printf("post set: %d\n", local);  // 2
        longjmp(buf, 1);
    } else {
        printf("post jmp: %d\n", local);  // 2
    }
}

int main() {
    jmper();
    return 0;
}