Guardian Procedure Calls Reference Manual

Considerations
• SIGLONGJMP_ is the TAL or pTAL procedure name for the C siglongjmp() function. The
C siglongjmp() function complies with the POSIX.1 standard.
• SIGLONGJMP_ does not return. Normally, return is made through the corresponding
SIGSETJMP_ procedure.
• Restoring the signal mask with this procedure enables a native process to receive multiple
occurrences of the same nondeferrable signal when this procedure is used to exit a signal
handler. If the signal mask is not restored and the same nondeferrable signal occurs a second
time, then the process terminates.
For details on deferrable and nondeferrable signals, see SIGACTION_INIT_ Procedure
(page 1362).
• The buffer pointed to by env is assumed to be valid and initialized by an earlier call to
SIGSETJMP_. If an invalid address is passed or if the caller modifies the jump buffer, the result
is undefined and could cause the system to deliver a nondeferrable signal to the process.
• If SIGLONGJMP_ detects an error, a SIGABRT or SIGILL signal is raised.
• If SIGLONGJMP_ is passed a jump buffer initialized by SETJMP_, then a simple long jump
(without restoring the signal mask) is executed.
• The jump buffer must be accessible to both the long jump procedure call and the associated
set jump procedure call.
• The procedure that invoked the corresponding call to SIGSETJMP_ must still be active; that is,
the activation record of the procedure that called SIGSETJMP_ must still be on the stack.
• A long jump across a transition boundary between the TNS and native mode environments,
in either direction, is not permitted. Any attempt to do so will be fatal to the process.
• A nonprivileged caller cannot jump to a privileged area. Any attempt to do so will be fatal
to the process. A privileged caller, however, can execute a long jump across the privilege
boundary; privileges are automatically turned off before control returns to the SIGSETJMP_
procedure.
• As a result of optimization, the values of nonvolatile local variables in the procedure that calls
SIGSETJMP_ might not be the same as they were when SIGLONGJMP_ was called if the
variables are modified between the calls to SIGSETJMP_ and SIGLONGJMP_. C and pTAL
programs can declare variables with the volatile type qualifier; this is the only safe way of
preserving local variables between calls to SIGSETJMP_ and SIGLONGJMP_. Alternatively,
you can make the variables global.
Example
SIGLONGJMP_ ( env, value );
Related Programming Manual
For programming information about the SIGLONGJMP_ procedure, see the Guardian Programmer's
Guide.
SIGLONGJMP_ Procedure 1375