Programming Forums > Application Development > C++

a1g0rithm · Mar 12th, 2006, 1:20 AM

i am writing a shell program with a history feature. i am reassigning sigint (ctrl-c) to print the history list. i am trying to use the gnu history library to manage the history, but it now segfaults on ctrl-c. here is the code:

setup signal handler;

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struct sigaction handler;
sigfillset(&handler.sa_mask);
handler.sa_handler = handle_SIGINT;
sigaction(SIGINT, &handler, NULL);

signal handling function:

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void handle_SIGINT(int signo)
{
	printf("sig\n");
}

now if the following line is in main, ctrl-c segfaults, if it is commented out, it works fine..

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add_history(*args);

i think that some other sig handling stuff is getting setup with gnu history, but i dont know what..
any help would be appreciated, if more info is needed, let me know.

grumpy · Mar 12th, 2006, 1:36 AM

Well, if the problem goes away when you comment out a call to add_history(), a fairly strong possibility is that the call of add_history() is the cause of the problem ...... which would mean the problem has nothing to the signal handling (the signal handling works incorrectly as a side-effect of an error by add_history()).

You haven't really provided enough information, but my guess is that add_history() assumes something about "args" that you are not honouring in main().

a1g0rithm · Mar 12th, 2006, 2:44 AM

thanks for the response.. i tracked down the problem...

the add_history function did not work well with the *args pointer.. it would complile and execute once fine, but segfault.. fixed by assigning *args contents to buffer var and passing this in to add_history.

Mar 12th, 2006, 1:20 AM	#1
a1g0rithm Newbie Join Date: Mar 2006 Posts: 2 Rep Power: 0	segfault using sigaction with gnu history i am writing a shell program with a history feature. i am reassigning sigint (ctrl-c) to print the history list. i am trying to use the gnu history library to manage the history, but it now segfaults on ctrl-c. here is the code: setup signal handler; (Toggle Plain Text) struct sigaction handler; sigfillset(&handler.sa_mask); handler.sa_handler = handle_SIGINT; sigaction(SIGINT, &handler, NULL); struct sigaction handler; sigfillset(&handler.sa_mask); handler.sa_handler = handle_SIGINT; sigaction(SIGINT, &handler, NULL); signal handling function: (Toggle Plain Text) void handle_SIGINT(int signo) { printf("sig\n"); } void handle_SIGINT(int signo) { printf("sig\n"); } now if the following line is in main, ctrl-c segfaults, if it is commented out, it works fine.. (Toggle Plain Text) add_history(args); add_history(args); i think that some other sig handling stuff is getting setup with gnu history, but i dont know what.. any help would be appreciated, if more info is needed, let me know.

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Mar 12th, 2006, 1:36 AM	#2
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,223 Rep Power: 5	Well, if the problem goes away when you comment out a call to add_history(), a fairly strong possibility is that the call of add_history() is the cause of the problem ...... which would mean the problem has nothing to the signal handling (the signal handling works incorrectly as a side-effect of an error by add_history()). You haven't really provided enough information, but my guess is that add_history() assumes something about "args" that you are not honouring in main().

Mar 12th, 2006, 2:44 AM	#3
a1g0rithm Newbie Join Date: Mar 2006 Posts: 2 Rep Power: 0	thanks for the response.. i tracked down the problem... the add_history function did not work well with the args pointer.. it would complile and execute once fine, but segfault.. fixed by assigning args contents to buffer var and passing this in to add_history.

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Programming Forums > Application Development > C++

segfault using sigaction with gnu history