Write a C program that does not terminate when Ctrl+C is pressed
Write a C program that doesn’t terminate when Ctrl+C is pressed. It prints a message “Cannot be terminated using Ctrl+c” and continues execution.
We can use signal handling in C for this. When Ctrl+C is pressed, SIGINT signal is generated, we can catch this signal and run our defined signal handler. C standard defines following 6 signals in signal.h header file.
SIGABRT – abnormal termination.
SIGFPE – floating point exception.
SIGILL – invalid instruction.
SIGINT – interactive attention request sent to the program.
SIGSEGV – invalid memory access.
SIGTERM – termination request sent to the program.
Additional signals are specified Unix and Unix-like operating systems (such as Linux) defines more than 15 additional signals. See http://en.wikipedia.org/wiki/
The standard C library function signal() can be used to set up a handler for any of the above signals.
/* A C program that does not terminate when Ctrl+C is pressed */#include <stdio.h>#include <signal.h> /* Signal Handler for SIGINT */void sigintHandler(int sig_num){ /* Reset handler to catch SIGINT next time. signal(SIGINT, sigintHandler); printf("\n Cannot be terminated using Ctrl+C \n"); fflush(stdout);} int main (){ /* Set the SIGINT (Ctrl-C) signal handler to sigintHandler signal(SIGINT, sigintHandler); /* Infinite loop */ while(1) { } return 0;} |
Output: When Ctrl+C was pressed two times
Cannot be terminated using Ctrl+C Cannot be terminated using Ctrl+C
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