During the developing phase of programs for my customers, I have to think that they can use the CTRL-C combo to interrupt the execution of my code.
In some cases, for example in a program that makes only some computations, I can avoid catching this event.
In some other cases, for example when my program has activated a hardware watchdog timer which will reset the system, I must handle this event to deactivate the hardware timer.
To handle this event I use the signal() function from the signal.h library.
void (*signal(int sig, void (*func)(int)))(int);
or in the equivalent but easier to read typedef'd version:
typedef void (*sig_t) (int);
sig_t signal(int sig, sig_t func);
This signal() facility is a simplified interface to the more general sigaction(2) facility.
Signals allow the manipulation of a process from outside its domain, as well as allowing the process to manipulate itself or copies of itself (children). for further information refer to man pages
man 3 signal
Here you are a sample program using the signal facility.
The signal() function at the start of main() function says that if there will be a CTRL-C (SIGNINT) event the control flow shall move to the safeExit() function. This function will perform all the operations needed to perform a safe exit from the program.
| safeExit.c – description |
| ——————- |
| begin : 24/06/2011 19.00 |
| copyright : ah ah ah |
| author : |
| email : |
| compiling : gcc -o safeExit safeExit.c |
| SYSTEM INCLUDES |
| PROTOTYPES |
void safeExit(int sig);
int main(int argc, char **argv);
void safeExit(int sig)
printf("CTRL-C received, exiting program\n");
int main(int argc, char **argv)