signals

问题 I have this below program #include <signal.h> #include <stdio.h> #include <unistd.h> int x = 1; void ouch(int sig) { printf("OUCH! dividing by zero!\n"); x = 0; } void fpe(int sig) { printf("FPE! I got a signal: %d\n",sig); psignal(sig, "psignal"); x = 1; } int main(void) { (void) signal(SIGINT, ouch); (void) signal(SIGFPE, fpe); while(1) { printf("Hello World: %d\n",1/x); sleep(1); } } Problem: While executing this program - when I give a SIGINT from the terminal to the program - the ""OUCH!

问题 I made the following program for learning the behavior of SIG_SETMASK . The following program is supposed to block SIGINT the interrupt signal until the func() function calls sigprocmask(SIG_SETMASK,&fOnemask,NULL); where as fOnemask is empty cuz no signals were store in sigset before it. But as I call sigprocmask(SIG_SETMASK,&fTwoCmask,NULL); inside func2() function before returning,where fTwomask contains previous signal list made by func() function, the program starts receiving signals and

问题 I am launching a simple Java application through Go, with the goal of proving that Go can send a signal like SIGQUIT or SIGTERM, and the Java can catch that and handle it appropriately (i.e. shutdown gracefully). When I run the Java program on the command line and send it a CTRL+C, the Java program correctly catches the signal. However, when I launch the Java program through Go and attempt to send the process a signal, the Java process is neither terminated nor does it handle the signal. The

问题 Here is my code to examine this: void handler(int n) { printf("handler %d\n", n); int status; if (wait(&status) < 0) printf("%s\n", strerror(errno)); } int main() { struct sigaction sig; sigemptyset(&sig.sa_mask); sig.sa_handler = handler; sig.sa_flags = 0; sig.sa_restorer = NULL; struct sigaction sigold; sigaction(SIGCHLD, &sig, &sigold); pid_t pid; int status; printf("before fork\n"); if ((pid = fork()) == 0) { _exit(127); } else if (pid > 0) { printf("before waitpid\n"); if (waitpid(pid,

问题 This post is related to: POSIX TIMER- Have multiple timers I want to call a function in the SignalHandler. This function is a TCP socket client(getSpeed). It gets data from a server every time the timer ticks one second and sends a signal which then calls the corresponding handler. First of all I am not sure if it is good practise to call a function from a signal handler. Now the problem is, my code freezes randomly whenever I execute this program which talks to a server. If this way of

问题 I'm using Qt charts module to draw a Nested Donuts chart just like the example in Qt Charts. And I want every components (QPieSlice) response to the mouse event, the hovered() signals work well, however, the clicked() signals only work for the QpieSlices in the last added QPieSerie. It seems other QpieSlices do not emit the signals, since if I explicitly call the clicked() function, the slot response correctly. This piece of code shows the issue Widget::Widget(QWidget *parent): QWidget(parent

问题 I want to resample my signal with to new time. Currently the sampling time of my signal is 0.01s , and the size of my signal and time array is 1*90001 . I am trying to use resample(x,p,q) in MATLAB, but I am a little bit confused. Can somebody suggest the right way to use this function and how to resample my data to rate of 0.02s instead of 0.01s ? Code - this is how I am trying to use resample , with example data. t = [0:0.03:1]; x = sin(4*pi*t); y = resample(x, 1, 2); ty = resample(t,1,2);

问题 This is a follow up question to this one. Take this simple example: public class Main { public static void main(String[] args) throws Exception { Runtime.getRuntime().exec("./child"); // This is just so that the JVM does not exit Thread.sleep(1000 * 1000); } } And here's the child process: #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <signal.h> void handle_sigquit(int sig) { printf("Signal %d received\n", sig); exit(1); } int main(int argc, char **argv) { signal(SIGQUIT

问题 #import <UIKit/UIKit.h> #import "XYZAppDelegate.h" int main(int argc, char * argv[]) { @autoreleasepool { return UIApplicationMain(argc, argv, nil, NSStringFromClass([XYZAppDelegate class])); } } The program works fine and I'm just curious about the case. The notification pointed at the 7th line and I could drag it among lines when I do so, a warning showed up warns me the moving of instruction pointer may cause serious problems. So, what's the instruction pointer? Can it disappear? I really

问题 Running a long-running sound processing app on tethered (to Xcode 3) iPod Touch. Twice now, after 1 hour 40 minutes the first time and 2 hours 20 minutes the second, the app has ended with signal 0. There are multiple discussions of signal 0 here and on other forums, and they all seem to blame running out of memory. But I dump the memory used at intervals, and, on the last test, it grew only about 3.3mb from early in the run until just before the end. And I have a hook in my app delegate to