signals

I am unable to trap a signal when running in a child / background process. Here is my simple bash script : #!/bin/bash echo "in child" trap "got_signal" SIGINT function got_signal { echo "trapped" exit 0 } while [ true ]; do sleep 2 done When running this and later do kill -SIGINT (pid) Everything works as expected, it prints 'trapped' and exits. Now, if I start the same script from a parent script like this : #!/bin/bash echo "starting the child" ./child.sh & Then the child does not trap the signal anymore.... ? After changing to use SIGTERM instead of SIGINT, it seems to be working correctly

Please explain this type signature : void (*signal(int signo, void *(func)(int)))(int) The type signature of the signal function is a bit more clear when a typedef is used for the function pointers that are passed around: typedef void (*sighandler_t)(int); sighandler_t signal(int signo, sighandler_t func); sighandler_t is a pointer to a function that takes an int parameter and returns nothing. The signal function takes such a function pointer as its second parameter. It also returns a function pointer of that type. C declarations need to be read from the inside out. The tricky part with

My original code passed a QStringList from the signal to the slot and then returned a QList. Everything worked fine but I needed to change both the QStringList and QList into 2 different subclassed QObjects. Since then I have been receiving errors like "synthesized method first required here" or it simply crashes without any error message. I understand that qt copies all arguments passed in a queued connection and a qobject cannot be copied. So instead of returning a qobject I thought I would create both qobjects prior to emitting the signal. Then I would pass references to each object, modify

I'm having some problems with communicating between Threads in PyQt. I'm using signals to communicate between two threads, a Sender and a Listener. The sender sends messages, which are expected to be received by the listener. However, no messages are receieved. Can anyone suggest what might be going wrong? I'm sure it must be something simple, but I've been looking around for hours and not found anything. Thanks in advance! from PyQt4 import QtCore,QtGui import time class Listener(QtCore.QThread): def __init__(self): super(Listener,self).__init__() def run(self): # just stay alive, waiting for

I try to implement the Fourier series function according to the following formulas: ...where... ...and... Here is my approach to the problem: import numpy as np import pylab as py # Define "x" range. x = np.linspace(0, 10, 1000) # Define "T", i.e functions' period. T = 2 L = T / 2 # "f(x)" function definition. def f(x): return np.sin(np.pi * 1000 * x) # "a" coefficient calculation. def a(n, L, accuracy = 1000): a, b = -L, L dx = (b - a) / accuracy integration = 0 for i in np.linspace(a, b, accuracy): x = a + i * dx integration += f(x) * np.cos((n * np.pi * x) / L) integration *= dx return (1 /

Is it possible to convert floating point exceptions (signals) into C++ exceptions on x86 Linux? This is for debugging purposes, so nonportability and imperfection is okay (e.g., if it isn't 100% guaranteed that all destructors are called). jwfearn If your C++ standard library implementation supports the TR1 functions fetestexcept , feraiseexcept and feclearexcept (mine doesn't yet so I can't test this) you can detect five kinds of floating point errors and then you can throw whatever exceptions you want. See here for a description of these functions. I also recommend section 12.3, "Managing