Table of Contents
Can I call exit from signal handler?
Calling an async-signal-unsafe function from a signal handler is perfectly legal unless the signal interrupted another async-signal-unsafe function.
What happens when signal handler returns?
After the signal handler completes, your code continues executing at the point where it was when the signal was received. If your code was executing a system call, it may fail with EINTR.
Can you call a function in a signal handler?
…the signal handler calls any function in the standard library other than the abort function, the _Exit function, the quick_exit function, or the signal function with the first argument equal to the signal number corresponding to the signal that caused the invocation of the handler.
What is Sigwinch Linux?
Introduction. SIGWINCH is a signal sent upon the resizing of a window: when the number of columns or rows changes, SIGWINCH is raised to the foreground processes attached to the terminal. The default disposition for this signal is to ignore it.
What is longjmp used for?
The call to longjmp is analogous to a throw statement, allowing an exception to return an error status directly to the setjmp .
What is the purpose of signal handler?
A signal handler is a function which is called by the target environment when the corresponding signal occurs. The target environment suspends execution of the program until the signal handler returns or calls longjmp() . Signal handlers can be set with signal() or sigaction() .
Does child process inherit signal handler?
a child process inherits signal settings from its parent during fork (). When process performs exec (), previously ignored signals remain ignored but installed handlers are set back to the default handler.
How do you ignore a signal?
If you want to ignore the signal specified by the first argument (i.e., pretending that the signal never happens), use SIG_IGN for the second argument. In the above two lines, SIGINT and SIGALRM are ignored. If you want the system to use the default way to handle a signal, use SIG_DFL for the second argument.
What is setjmp and longjmp used for?
Setjmp()and longjmp()are usually used so that if an error is detected within a long string of procedure calls, the error may be dealt with efficiently by longjmp-ing out of the procedure that catches the error. This avoids having to return from each procedure can test return values.
Is longjmp () async-signal safe in multithreaded programs?
Some kind of subtle or unsubtle chaos is sure to result. If, in a multithreaded program, a longjmp () call employs an env buffer that was initialized by a call to setjmp () in a different thread, the behavior is undefined. POSIX.1-2008 Technical Corrigendum 2 adds longjmp () and siglongjmp () to the list of async-signal-safe functions.
What is the difference between longjmp () and sigsetjmp and siglongjmp?
setjmp () and sigsetjmp () return 0 when called directly; on the “fake” return that occurs after longjmp () or siglongjmp (), the nonzero value specified in val is returned. The longjmp () or siglongjmp () functions do not return.