setjmp/longjmp not works

[moien007]

Look at the following code:

#include<stdio.h>
#include<stdint.h>
#include<stdlib.h>
#include<stdbool.h>
#include<setjmp.h>
#include<string.h>

typedef struct {
  jmp_buf jump_buffer;
  uint32_t error_code;
  char *error_desc;
} exception_t;

void exception_throw(exception_t * e, uint32_t error_code, char *error_desc)
{
  e->error_code = error_code;
  e->error_desc = error_desc;
  longjmp(e->jump_buffer, 1);
}

bool exception_catch(exception_t * e)
{
  return setjmp(e->jump_buffer);
}

int main()
{
  exception_t ex;
  memset(&ex, 0, sizeof(exception_t));

  if (exception_catch(&ex)) {
    printf("exception thrown: %s", ex.error_desc);
    return ex.error_code;
  } else {
    exception_throw(&ex, 1337, "fun");
  }

  return 0;
}

Why?

[GReaper]

If the function that called setjmp has exited, the behavior is undefined (in other words, only long jumps up the call stack are allowed)

exception_catch() exits in order to jump to the else clause.

[moien007]

exception_catch() exits in order to jump to the else clause.

Thanks for the response.