This scenario describes the behavior of an application that contains a COBOL and a Fortran routine. Refer to Figure 1 throughout the following discussion. In this scenario, a Fortran main routine invokes a COBOL subroutine. An exception occurs in the COBOL subroutine.

Figure 1. Stack contents when the exception occurs

The actions taken follow the three Language Environment condition handling steps: enablement, condition, and termination imminent.

1. In the enablement step, COBOL determines whether the exception that occurred should be handled as a condition.
   • If the exception is to be ignored, control is returned to the next sequential instruction after where the exception occurred.
   • If the exception is to be enabled and processed as a condition, the condition handling step, described below, takes place.
2. If a user-written condition handler has been registered using CEEHDLR on the COBOL stack frame, it is given control. If it issues a resume, the condition handling step ends. Processing continues in the routine to which the resume cursor points.

   Two areas to watch out for here are resuming from an IBM® condition of severity 2 or greater (see the chapter on coding a user-written condition handler in z/OS Language Environment Programming Guide) and moving the resume cursor in an application that contains a COBOL program (see GOTO out-of-block and move resume cursor).

   In this example, no user-written condition handler is registered for the condition, so the condition is percolated.

3. If the condition has a Facility_ID of IGZ, the condition is COBOL-specific. The COBOL default actions occur. If COBOL doesn't recognize the condition, condition handling continues.
4. There is no user-written condition handler on the Fortran stack frame (because CEEHDLR cannot be called from a Fortran routine), and the condition is percolated.
5. If the condition is of severity 0 or 1, Language Environment default actions take place, as described in Table 1.
6. If the condition is of severity 2 or above, Language Environment default action is to promote the condition to T_I_U (Termination Imminent due to an Unhandled condition) and redrive the stack. Condition handling now enters the termination imminent step.
7. If on the second pass of the stack no condition handler moves the resume cursor and issues a resume, Language Environment terminates the thread.