I don't know if that's the way to gain daemon behavior. If you fork twice, your process stills attached to the controlling terminal. I guess you could finish that terminal session without problem. But I think that a real daemon has to detach him self from the controlling tty. You can do that, like Raghu said, calling setpgrp and setsid and closing stdout an err. There is also a function in unistd that does all of this for you.
int daemon(int nochdir,int noclose); (see "man daemon") Don't know if exists in all unix or linux distros. But it seems to work. Saludos. Manuk -----Mensaje original----- De: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] nombre de John T. Williams Enviado el: Martes, 23 de Septiembre de 2003 13:07 Para: [EMAIL PROTECTED]; John T. Williams CC: Silambu Chelvan; [EMAIL PROTECTED]; [EMAIL PROTECTED] Asunto: Re: Switching between foreground and background I have to admit that I don't know why, but every resource I've ever read about causing programs to gain daemon behavior has involved forking 2 times and then starting the program code. If anyone here does know why, I'd would be happy to hear it. ----- Original Message ----- From: "Raghuveer" <[EMAIL PROTECTED]> To: "John T. Williams" <[EMAIL PROTECTED]> Cc: "Silambu Chelvan" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Tuesday, September 23, 2003 7:01 AM Subject: Re: Switching between foreground and background > John T. Williams wrote: > > >I think part of the problem here might be conceptual. > > > >If I understand what you want, you'd like, on a signal, for your program to > >go into the background (still running but no longer blocking the terminal > >input/output). On another signal you would like the program to come back to > >the foreground. > > > >If this is the case, the problem you're facing is that the program being in > >the foreground and the background is actually part of the shell, not a > >property of the program running. Most Shells provide a way to switch > >programs from the foreground to the background and back. > >BASH for example I could type > > > >$>./myprogram > >(cntr + Z) //suspends the current program and prings the prompt back > >$>bg (runs the program in the background) > > > >The only way that I know of to force a program to run in the background in > >the code is to make it a daemon which is done by forking twice > > > >int main( ) { > > if(fork()==0) { > > if( fork() == 0 ) { > > program code starts here > > } > > exit(0); > > } > > exit(0); > >} > > > > > I don't feel it's required to fork() twice for making it a daemon, once > is enough. Ya, but should use setpgrp() or setpid() and close stdin, out > and err after the fork and go to infinite loop. > > -Raghu > > > > >----- Original Message ----- > >From: "Silambu Chelvan" <[EMAIL PROTECTED]> > >To: <[EMAIL PROTECTED]> > >Sent: Monday, September 22, 2003 6:48 AM > >Subject: Switching between foreground and background > > > > > > > > > >>Hi all, > >> > >>I have written some program with signal handler. Is > >>this possible, if > >>one of the signals registered with my program is > >>raised, my program > >>should goto background and should come to foreground > >>when some other of the > >>registered signal is raised. how to do it? > >> > >>Any function available to switch a process between > >>foreground and > >>background at runtime? > >> > >>with regards, > >>M. SilambuChelvan > >> > >> > >>__________________________________ > >>Do you Yahoo!? > >>Yahoo! SiteBuilder - Free, easy-to-use web site design software > >>http://sitebuilder.yahoo.com > >>- > >>To unsubscribe from this list: send the line "unsubscribe linux-newbie" in > >>the body of a message to [EMAIL PROTECTED] > >>More majordomo info at http://vger.kernel.org/majordomo-info.html > >>Please read the FAQ at http://www.linux-learn.org/faqs > >> > >> > > > >- > >To unsubscribe from this list: send the line "unsubscribe linux-newbie" in > >the body of a message to [EMAIL PROTECTED] > >More majordomo info at http://vger.kernel.org/majordomo-info.html > >Please read the FAQ at http://www.linux-learn.org/faqs > > > > > > > > > - > To unsubscribe from this list: send the line "unsubscribe linux-newbie" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.linux-learn.org/faqs - To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs
