books/apue/longjump.c

   1 /*
   2  * setjmp() and longjmp() example usage
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <setjmp.h>
   8
   9 static jmp_buf jmpbuffer;
  10
  11 static void f2(void)
  12 {
  13         longjmp(jmpbuffer, 1);
  14 }
  15
  16 static void f1(int i, int j, int k)
  17 {
  18         printf("in f1(): count = %d, val = %d, sum = %d\n", i, j, k);
  19         f2();
  20 }
  21
  22 int main(void)
  23 {
  24         int count;
  25         register int val;
  26         volatile int sum;
  27
  28         count = 2; val = 3; sum = 4;
  29         if (setjmp(jmpbuffer) != 0) {
  30                 printf("after longjmp: count = %d, val = %d, sum = %d\n",
  31                        count, val, sum);
  32                 exit(0);
  33         }
  34
  35         count = 97; val = 98; sum = 99;
  36         f1(count, val, sum);    /* never returns */
  37         return 0;
  38 }