aculongjmp()

This aculongjmp() routine cuts the C and COBOL call stacks to the point recorded in passed "acujmp_buf". This point must have been recorded by a prior call to both acusavenv() and setjmp(). Once a state has been recorded, you can only jump to it one time using aculongjmp(). After that, it must be recorded again.

Usage

void
 
aculongjmp(acujmp_buf *buffer)

Return Values

This routine does not return; instead, it internally calls the C library longjmp() routine which transfers control to the point of the prior setjmp() call and causes setjmp() to return a value of "1".

Example

#include "acusetjmp.h"
acujmp_buf  mark1;

/* A COBOL or 'C' subroutine can CALL "myexception" to transfer 
/* control 
back to the point where "mark1" was recorded.  */

void myexception()
{
aculongjmp( &mark1 );
}

/* Prototypical 'C' service routine to run a COBOL program with 
/* the ability
 to exit out of the COBOL code via call to 
/* 'myexception' */

void myservice()

{
/* Record our position in the 'C' and COBOL call stacks.
/* 'Setjmp' will return "0" when executed first. We
/* call it in a "while" loop so that the location 
/* recording re-executes in case we end
/* up jumping here via 'aculongjmp' */
while( setjmp( *acusavenv(&mark1) ) ) 
{
/* If we get here, it's because 'aculongjmp' jumped 
/* here. Put recovery/cleanup code here.
/* If you do not want to re-execute the COBOL routine,
/* add
 a "return" here.  Otherwise, just fall out of the
/* while
 loop to re-execute the COBOL routine */
}

/* Setup to call COBOL here and call a COBOL routine */
/* The COBOL program can jump back to the top of this 
/* routine by calling "myexception" at some point.  This 
/* will transfer control to the point of the 'setjmp' 
/* call above and cause 'setjmp' to return "1".  */

struct a_cobol_info cblinfo; 
memset(&cblinfo, 0, sizeof(cblinfo)); 
cblinfo.a_cobol_info_size = sizeof(cblinfo); 
cblinfo.pgm_name = "cblprog"; 
cblinfo.num_params = 0; 
cblinfo.params = NULL; 
acu_cobol(&cblinfo); 
}

Restrictions

• As with setjmp(), the function that calls acusavenv() must not exit before any calls to aculongjmp() that use the same buffer. Programs that do this will have undefined (and usually fatal) results.
• aculongjmp() works by simulating EXIT PROGRAM statements for each of the COBOL programs being exited. This EXIT PROGRAM has all its normal effects. If a program cannot exit for some reason, the call to aculongjmp() fails and the runtime shuts down with a fatal error. Reasons that EXIT PROGRAM can fail include:
  • The program is the main program.
  • The program is currently running an event procedure.
  • The program is the root program of a thread.
  • The program is currently in a Declarative called directly by the BULK-ADDITION feature of Vision.
• Because the caller of aculongjmp() must be in the same run unit as the caller of the corresponding acusavenv(), avoid using the CHAIN verb.
• The caller of aculongjmp() must be in the same COBOL thread as the caller of the corresponding acusavenv(). In addition, the effect of aculongjmp() on other COBOL threads is undefined. We recommend that you stop any other threads prior to calling aculongjmp().
• After aculongjmp() uses a buffer, that buffer is no longer valid and must be re-recorded by a new call to acusavenv() and setjmp(). This behavior is different from the normal setjmp()/longjmp() convention. If converting existing setjmp() logic, you can usually accomplish this by replacing the "if" statement that contains the call to setjmp() with a "while" statement. For example:

  if ( setjmp(mybuf) == 1 )
  {
  /* longjmp lands here */
  }
  becomes:
  while ( setjmp(*acusavenv(&myacubuf)) == 1 )
  {
  /* aculongjmp lands here */
  }