The limitation of this facility is that it cannot work for SIGKILL. */
/* Register a cleanup function to be executed when a catchable fatal signal
- occurs. */
+ occurs.
+
+ Restrictions for the cleanup function:
+ - The cleanup function can do all kinds of system calls.
+ - It can also access application dependent memory locations and data
+ structures provided they are in a consistent state. One way to ensure
+ this is through block_fatal_signals()/unblock_fatal_signals(), see
+ below. Another - more tricky - way to ensure this is the careful use
+ of 'volatile'.
+ However,
+ - malloc() and similarly complex facilities are not safe to be called
+ because they are not guaranteed to be in a consistent state.
+ - Also, the cleanup function must not block the catchable fatal signals
+ and leave them blocked upon return.
+
+ The cleanup function is executed asynchronously. It is unspecified
+ whether during its execution the catchable fatal signals are blocked
+ or not. */
extern void at_fatal_signal (void (*function) (void));
functions create the temporary file or directory _before_ returning its
name to the application. */
-/* Temporarily delay the catchable fatal signals. */
+/* Temporarily delay the catchable fatal signals.
+ The signals will be blocked (= delayed) until the next call to
+ unblock_fatal_signals(). If the signals are already blocked, a further
+ call to block_fatal_signals() has no effect. */
extern void block_fatal_signals (void);
/* Stop delaying the catchable fatal signals. */