Micro Focus Studio Enterprise Edition for Windows > General Reference > C Functions for Calling COBOL > coblongjmp

coblongjmp

With the cobsetjmp function, provides the capability of a non-local GO TO, for use in error or exception handling.

Restriction:

This function is supported for native COBOL only.

Syntax:

#include "cobsetjmp.h"

void coblongjmp(struct cobjmp_buf *buf);

Parameters:

buf

A buffer in which the current execution environment is saved.

Comments:

The cobsetjmp() function saves the environment of the current COBOL program and C function in the buffer pointed to by buf. It calls the C library function setjmp(), which immediately returns a value of 0.

A subsequent call to coblongjmp() either from elsewhere in the C function that called cobsetjmp(), or from one of its C or COBOL subprograms, causes execution to be resumed at the point immediately after the call to cobsetjmp().

After calling coblongjmp(), cobsetjmp() returns a non-zero value, thus enabling the value to be tested after the cobsetjmp() call.

The following restrictions apply when using the coblongjmp() and cobsetjmp() functions:

cobsetjmp() and coblongjmp can be called from a C program only; they cannot be called from COBOL.
coblongjmp() must be called from the same or from a lower level in the CALL/PERFORM hierarchy of control flow as cobsetjmp(). In the intervening time, control must not have been returned to a higher level. Specifically, control must not have been returned from the C function that called cobsetjmp().
If coblongjmp() returns control to a different call level than that used by cobsetjmp(), programs exited by this mechanism appear to have been exited normally and can be called again later in the program's run.
coblongjmp cannot be used if a CHAIN has been made since cobsetjmp was last called.
coblongjmp() cannot be used in an error procedure, exit procedure or signal handler.

Equivalent COBOL Syntax:

None.

Example:

The following shows how to use the coblongjmp() and cobsetjmp() functions:

void
some_c_func(void)
{
    struct cobjmp_buf buf;

    if (cobsetjmp(&buf) != 0)
    {
        cobprintf("Returned from coblongjmp\n");
        return;
    }
  
    /* Valid code here - for example can call COBOL */

    coblongjmp(&cobjmp_buf);
}