signals

[zwetan]

we need to be able to manage those signals in a cross-platform way

SIGABRT - abort
SIGALRM - alarm
SIGHUP - Hangup
SIGINT - interrupt
SIGKILL - kill
SIGTERM - terminate

[zwetan]

different set of problems

Under Windows signal()
support only a subset of signals

sig value	Description
SIGABRT	Abnormal termination
SIGFPE	Floating-point error
SIGILL	Illegal instruction
SIGINT	CTRL+C signal
SIGSEGV	Illegal storage access
SIGTERM	Termination request

but wait ...

SIGINT is not supported for any Win32 application. When a CTRL+C interrupt occurs,
Win32 operating systems generate a new thread to specifically handle that interrupt.
This can cause a single-thread application, such as one in UNIX, to become
multithreaded and cause unexpected behavior.

so you want to use SetConsoleCtrlHandler to handle SIGINT

signal	WIN32	keyboard	char
SIGABRT	SIGABRT
SIGALRM	timeSetEvent
SIGINT	CTRL_C_EVENT	CTRL+C	^C
SIGBREAK	CTRL_BREAK_EVENT	CTRL+BREAK	?
SIGHUP	CTRL_CLOSE_EVENT	user close the console
	CTRL_LOGOFF_EVENT	user logoff
	CTRL_SHUTDOWN_EVENT	user shutdown the system
SIGTERM	SIGTERM
SIGTSTP	???	CTRL+Z	^Z

also note from WinAPI WIN32HandlerRoutine

The system also displays the dialog box if the process does not respond
within a certain time-out period (5 seconds for CTRL_CLOSE_EVENT,
and 20 seconds for CTRL_LOGOFF_EVENT and CTRL_SHUTDOWN_EVENT).

[zwetan]

basic design is to handle the signals through the Program class
as it is a "special" class we can access from ShellCore.

for each signals we basically set a flag to true
then in the "main loop" we check the flag to raise the user assigned callback

example with SIGHUP

Program.onHangup( f:Function );

we store the callback function on the primordial thread
and then we call the native function

ProgramClass::_setHangupMonitor()

which then use the Platform.h interface

Platform::GetInstance()->setHangup(localHangupCallback, this);

A simple getter allow us to know if the flag is true or false

Program.hangedup

then in the "main loop" signalPending allow us to know if there are
one or more signals pending and call _handleSignals()
eg.

private function _handleSignals():void
{
    //SIGHUP
    if( Program.hangedup )
    {
        //...
        Program.runHangupCallback();
        //...
    }
}

if the callback does not exists, case where we pass a null
eg. Program.onHangup( null )

or if the "main loop" is not running

the signal will be caught but no actions happen
eg. a SIGHUP will not hangup the actual program