On Tue, 07 Jun 2005 19:07:47 +0200, Geert wrote:

> Thanks, but the program will continue to be connected to the shell try this for instance:
> 
> extern (C) int fork ();
> void main()
> {
> 	// fork returns -1 on failure
> 	// 0 to childprocess, and the pid
> 	// number of the child process to the parent
> 	if(fork()) exit(0);
> 
> 	while(1)
> 		printf("You will see this output.\n");
> }

Well yes it's still attached to the shell of its parent process (until the shell is closed, of course), but a daemon doesn't print on stdout anyway, so that shouldn't be a problem...

Geert try to write to some log-file and most likely it will continue to fill it with bytes after you close the shell. :)

-- 
...........
Dejan Lekic
  http://dejan.lekic.org

The correct way to detach from the shell (and I've written a server app that does this, just don't have the code with me ATM (at work)) is to create a different session ID and then fork and kill the parent.

You might want to install some signal handlers in your server if you go this way.  In your signal handler for SIGINT and SIGTERM you'll want to copy/paste the code from internal/dmain2.d in phobos that terminates D:

: 	_moduleDtor();
:	gc_term();
:    }
:    catch (Object o)
:    {
:	printf("Error: ");
:	o.print();
:	exit(EXIT_FAILURE);
:    }
:
:    version (linux)
:    {
:	free(am);
:	_STD_critical_term();
:	_STD_monitor_staticdtor();
:    }

I recall that it was a true pain to get D to terminate the program correctly when you have multiple threads running and you're interrupted by a signal. Horrible stuff.  I wish phobos had a nice "guaranteed cleanup" system, in case of emergency death of app.

It is possible to do this easily in your own application, but you'd have to create a Windows-specific and a Linux-specific version of the code that does this.  Phobos just feels like a great place for this functionality.  If this becomes the case, I have some code for Linux I'd like to contribute!  However, I don't know jack squat about the Windows side of things...


P.S. - I promise you I'll get you the code for this when I get home (in 4 hours
or so).

In article <d84lom$2ql7$1@digitaldaemon.com>, Dejan Lekic says...
>
>Geert try to write to some log-file and most likely it will continue to fill it with bytes after you close the shell. :)
>
>-- 
>...........
>Dejan Lekic
>  http://dejan.lekic.org
> 

Regards,
James Dunne

And, as promised (later than I had hoped for - I apologize), your linux daemon
in D:

:import	std.c.stdlib;
:version (linux) import std.c.linux.linux;
:
:extern (C) {
:	/// These are for control of termination:
:	void _STD_monitor_staticdtor();
:	void _STD_critical_term();
:	void gc_term();
:	void _moduleDtor();
:
:	version (linux) {
:		alias	int pid_t;
:
:		// daemon functions:
:		pid_t fork();
:		int umask(int);
:		int setsid();
:		int close(int fd);
:
:		// Signal trapping in Linux:
:		typedef void (*sighandler_t)(int);
:		sighandler_t signal(int signum, sighandler_t handler);
:
:		void sighandler(int sig) {
:			write_log("signal %d caught...", sig);
:			terminate();
:		}
:	}
:}
;
:void terminate() {
:	// Custom termination code here:
:
:
:	// Phobos termination (since we can't really make main() return):
:	_moduleDtor();
:	gc_term();
:	version (linux) {
:		//free(am);
:		_STD_critical_term();
:		_STD_monitor_staticdtor();
:	}
:
:	exit(0);
:}
:
:int main(char[][] args) {
:	debug {
:	} else {
:		// Daemonize under Linux:
:		version (linux) {
:			// Our process ID and Session ID
:			pid_t pid, sid;
:
:			// Fork off the parent process
:			pid = fork();
:			if (pid < 0) {
:				exit(EXIT_FAILURE);
:			}
:			// If we got a good PID, then we can exit the parent :process.
:			if (pid > 0) {
:				exit(EXIT_SUCCESS);
:			}
:
:			// Change the file mode mask
:			umask(0);
:		}
:	}
:
:	// Open a log file here:
:
:
:	debug {	} else {
:		version (linux) {
:			// Create a new SID for the child process
:			sid = setsid();
:			if (sid < 0) terminate();
:
:			// Close out the standard file descriptors
:			close(0);
:			close(1);
:			close(2);
:		}
:	}
:
:	version (linux) {
:		signal(SIGABRT, &sighandler);
:		signal(SIGTERM, &sighandler);
:		signal(SIGQUIT, &sighandler);
:		signal(SIGINT, &sighandler);
:	}
:
:	try {
:		// Do your main loop here
:	} catch (ex as Exception) {
:		// Catch an exception
:	} finally {
:		// Terminate the server
:		terminate();
:	}
:
:	return 0;
:}

Hope this helps! =)

In article <d84psn$2uga$1@digitaldaemon.com>, James Dunne says...
>
>The correct way to detach from the shell (and I've written a server app that does this, just don't have the code with me ATM (at work)) is to create a different session ID and then fork and kill the parent.
>
>You might want to install some signal handlers in your server if you go this way.  In your signal handler for SIGINT and SIGTERM you'll want to copy/paste the code from internal/dmain2.d in phobos that terminates D:
>
>: 	_moduleDtor();
>:	gc_term();
>:    }
>:    catch (Object o)
>:    {
>:	printf("Error: ");
>:	o.print();
>:	exit(EXIT_FAILURE);
>:    }
>:
>:    version (linux)
>:    {
>:	free(am);
>:	_STD_critical_term();
>:	_STD_monitor_staticdtor();
>:    }
>
>I recall that it was a true pain to get D to terminate the program correctly when you have multiple threads running and you're interrupted by a signal. Horrible stuff.  I wish phobos had a nice "guaranteed cleanup" system, in case of emergency death of app.
>
>It is possible to do this easily in your own application, but you'd have to create a Windows-specific and a Linux-specific version of the code that does this.  Phobos just feels like a great place for this functionality.  If this becomes the case, I have some code for Linux I'd like to contribute!  However, I don't know jack squat about the Windows side of things...
>
>
>P.S. - I promise you I'll get you the code for this when I get home (in 4 hours
>or so).
>
>In article <d84lom$2ql7$1@digitaldaemon.com>, Dejan Lekic says...
>>
>>Geert try to write to some log-file and most likely it will continue to fill it with bytes after you close the shell. :)
>>
>>-- 
>>...........
>>Dejan Lekic
>>  http://dejan.lekic.org
>> 
>
>Regards,
>James Dunne

Regards,
James Dunne

Thanks it sure helps!

James Dunne wrote:
> And, as promised (later than I had hoped for - I apologize), your linux daemon
> in D:
> 
> :import	std.c.stdlib;
> :version (linux) import std.c.linux.linux;
> :
> :extern (C) {
> :	/// These are for control of termination:
> :	void _STD_monitor_staticdtor();
> :	void _STD_critical_term();
> :	void gc_term();
> :	void _moduleDtor();
> :
> :	version (linux) {
> :		alias	int pid_t;
> :
> :		// daemon functions:
> :		pid_t fork();
> :		int umask(int);
> :		int setsid();
> :		int close(int fd);
> :
> :		// Signal trapping in Linux:
> :		typedef void (*sighandler_t)(int);
> :		sighandler_t signal(int signum, sighandler_t handler);
> :
> :		void sighandler(int sig) {
> :			write_log("signal %d caught...", sig);
> :			terminate();
> :		}
> :	}
> :}
> ;
> :void terminate() {
> :	// Custom termination code here:
> :
> :
> :	// Phobos termination (since we can't really make main() return):
> :	_moduleDtor();
> :	gc_term();
> :	version (linux) {
> :		//free(am);
> :		_STD_critical_term();
> :		_STD_monitor_staticdtor();
> :	}
> :
> :	exit(0);
> :}
> :
> :int main(char[][] args) {
> :	debug {
> :	} else {
> :		// Daemonize under Linux:
> :		version (linux) {
> :			// Our process ID and Session ID
> :			pid_t pid, sid;
> :
> :			// Fork off the parent process
> :			pid = fork();
> :			if (pid < 0) {
> :				exit(EXIT_FAILURE);
> :			}
> :			// If we got a good PID, then we can exit the parent :process.
> :			if (pid > 0) {
> :				exit(EXIT_SUCCESS);
> :			}
> :
> :			// Change the file mode mask
> :			umask(0);
> :		}
> :	}
> :
> :	// Open a log file here:
> :
> :
> :	debug {	} else {
> :		version (linux) {
> :			// Create a new SID for the child process
> :			sid = setsid();
> :			if (sid < 0) terminate();
> :
> :			// Close out the standard file descriptors
> :			close(0);
> :			close(1);
> :			close(2);
> :		}
> :	}
> :
> :	version (linux) {
> :		signal(SIGABRT, &sighandler);
> :		signal(SIGTERM, &sighandler);
> :		signal(SIGQUIT, &sighandler);
> :		signal(SIGINT, &sighandler);
> :	}
> :
> :	try {
> :		// Do your main loop here
> :	} catch (ex as Exception) {
> :		// Catch an exception
> :	} finally {
> :		// Terminate the server
> :		terminate();
> :	}
> :
> :	return 0;
> :}
> 
> Hope this helps! =)
> 
> In article <d84psn$2uga$1@digitaldaemon.com>, James Dunne says...
> 
>>The correct way to detach from the shell (and I've written a server app that
>>does this, just don't have the code with me ATM (at work)) is to create a
>>different session ID and then fork and kill the parent.
>>
>>You might want to install some signal handlers in your server if you go this
>>way.  In your signal handler for SIGINT and SIGTERM you'll want to copy/paste
>>the code from internal/dmain2.d in phobos that terminates D:
>>
>>: 	_moduleDtor();
>>:	gc_term();
>>:    }
>>:    catch (Object o)
>>:    {
>>:	printf("Error: ");
>>:	o.print();
>>:	exit(EXIT_FAILURE);
>>:    }
>>:
>>:    version (linux)
>>:    {
>>:	free(am);
>>:	_STD_critical_term();
>>:	_STD_monitor_staticdtor();
>>:    }
>>
>>I recall that it was a true pain to get D to terminate the program correctly
>>when you have multiple threads running and you're interrupted by a signal.
>>Horrible stuff.  I wish phobos had a nice "guaranteed cleanup" system, in case
>>of emergency death of app.
>>
>>It is possible to do this easily in your own application, but you'd have to
>>create a Windows-specific and a Linux-specific version of the code that does
>>this.  Phobos just feels like a great place for this functionality.  If this
>>becomes the case, I have some code for Linux I'd like to contribute!  However, I
>>don't know jack squat about the Windows side of things...
>>
>>
>>P.S. - I promise you I'll get you the code for this when I get home (in 4 hours
>>or so).
>>
>>In article <d84lom$2ql7$1@digitaldaemon.com>, Dejan Lekic says...
>>
>>>Geert try to write to some log-file and most likely it will continue to fill
>>>it with bytes after you close the shell. :)
>>>
>>>-- 
>>>...........
>>>Dejan Lekic
>>> http://dejan.lekic.org
>>> 
>>
>>Regards,
>>James Dunne
> 
> 
> Regards,
> James Dunne