longjmp

2.8.3 longjmp

Declaration:

void longjmp(jmp_buf environment, int value);

Causes the environment to be restored from a setjmp call where the environment variable had been saved. It causes execution to goto the setjmp location as ifsetjmp had returned the value of the variable value. The variable value cannot be zero. However, if zero is passed, then 1 is replaced. If the function where setjmpwas called has terminated, then the results are undefined.

Example:

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

void some_function(jmp_buf);

int main(void)
{
  int value;
  jmp_buf environment_buffer;

  value=setjmp(environment_buffer);
  if(value!=0)
   {
    printf("Reached this point from a longjmp with value=%d.\n",value);
    exit(0);
   }
  printf("Calling function.\n");
  some_function(environment_buffer);
  return 0;
}

void some_function(jmp_buf env_buf)
{
  longjmp(env_buf,5);
}

The output from this program should be:

Calling function.
Reached this point from a longjmp with value=5.
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