c++/3056: gcc 2.95.3 -- atexit not catching exit() call following longjmp

[doug dot hackworth at nomos dot com]

>Number:         3056
>Category:       c++
>Synopsis:       gcc 2.95.3 -- atexit not catching exit() call following longjmp
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jun 05 10:16:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Doug Hackworth
>Release:        gcc version 2.95.3 20010315 (release)
>Organization:
>Environment:
i386-pc-solaris2.6
uname -a .... SunOS corvus2s 5.6 Generic_105182-19 i86pc i386 i86pc
>Description:

GCC does not generate an error message.  The code compiles and
runs, but seems to run incorrectly.  

All code is in the attached file, TestTerminate.cpp.  There 
are no include files.

A function (here called "Terminate()") is specified by 
atexit() to be executed when exit() is called.  Also, setjmp() 
is used to specify a stack-restoration point.  When exit() 
is called once, the function Terminate() executes.  

Within Terminate, atexit() is used again to re-register 
Terminate as the function to be executed upon exiting (it 
is re-registered because, since it's been called once, it 
has been removed from the stack); atexit returns 0, and 
thus appears to be working correctly.  Following this, 
there is a longjmp() call, and this sends control back to 
the setjmp point in main().  

When program execution resumes from this point, exit() is 
called a second time.  However, instead of calling 
Terminate as it should do, the program exits.  

>How-To-Repeat:
// ALSO IN ATTACHED FILE (from gnatsweb)

extern "C" {
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <setjmp.h>
//#include <sys/param.h>
//#include <sys/types.h>
//#include <sys/stat.h>
}

jmp_buf envJmp;

//================================

void Terminate(void)
{
		fflush(stdout);
		printf("SETTING FOR TERMINATION\n");
		int i = atexit(Terminate); 
		printf("SETTING AFTER TERMINATION %d\n",i);
		longjmp(envJmp, 1); 
}

//================================

int main(void)
{
  atexit(Terminate);


  if (setjmp(envJmp) == 0)
	  {
		printf("Try One\n");
		exit(1);
	  }

  if (setjmp(envJmp) == 0)
	  {
		printf("Try Two\n");
	    exit(2);
	  }  

  printf("Exiting...\n");

  exit(0);
}
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
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