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  • Django "comment_was_flagged" signal

    - by tsoporan
    Hello, This is my first time working with django signals and I would like to hook the "comment_was_flagged" signal provided by the comments app to notify me when a comment is flagged. This is my code, but it doesn't seem to work, am I missing something? from django.contrib.comments.signals import comment_was_flagged from django.core.mail import send_mail def comment_flagged_notification(sender, **kwargs): send_mail('testing moderation', 'testing', 'test@localhost', ['[email protected]',]) comment_was_flagged.connect(comment_flagged_notification) (I am just testing the email for now, but I have assured the email is sending properly.) Thanks!

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  • Signal Handling in C

    - by Dave
    How can I implement signal Handling for Ctrl-C and Ctrl-D in C....So If Ctrl-C is pressed then the program will ignore and try to get the input from the user again...If Ctrl-D is pressed then the program will terminate... My program follows: int main(){ char msg[400]; while(1){ printf("Enter: "); fgets(msg,400,stdin); printf("%s\n",msg); } } Thanks, Dave

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  • Signal processing or algorithmic programming for a PLC

    - by james singen smythe
    I have an application that takes voltages and temperatures as analog inputs and does some processing using an algorithm which involves signal processing such as low-pass filtering, exponential smoothing, and other steps which might typically be done in a high-level programming language such as C or C++. I'm curious how I could perform these same steps using a PLC, and in particular, the Allen-Bradley Control-Logix system? It seems to me that the instruction set with ladder logic is too limited for this. Could I perform this using structured text?

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  • Agilent E4426B signal generator locks up during multiple GPIB *SAV operations

    - by aspiehler
    I have a test fixture with an Agilent E4426B RF signal generator connected to a PC via a National Instrument Ethernet-to-GPIB bridge. My software is attempting to sanitize the instrument by presetting it and then saving the current state to all of the memory locations writable via the standard SCPI command "*SAV x,y". The loop works to a point, but eventually the instrument responds with an error and continuously displays the "L" icon on the front display and a "Remote preset" message at the bottom. At that point it won't respond to any more remote commands and I have to either cycle power or press LOCAL, then PRESET at which point it takes about 3 minutes to finish presetting. At that point the "L" icon is still present and and the next GPIB command sent to the instrument causes it to report a -113 error (undefined header) in the instrument error queue. I fired up NI spy to see what was happening, and found that the error was happening at the same point in the loop - "*SAV 6,2" in this case. From NI Spy: Send (0, 0x0017, "*SAV 6,2", 8 (0x8), NLend (0,0x01)) Process ID: 0x00000520 Thread ID: 0x00000518 ibsta:0xc168 iberr: 6 ibcntl: 2(0x2) And here's the code from the instrument driver: int CHP_E4426b::Erase() { if ((m_StatusCode = Initialize()) != GPIB_SUCCESS) // basically just sends "*RST" return m_StatusCode; m_SaveState = "*SAV %d, %d"; for (int i=0; i < 10; i++) for (int j=0; j < 100; j++) { sprintf(m_CmdString, m_SaveState, j, i); if ((m_StatusCode = Send(m_CmdString, strlen(m_CmdString))) != GPIB_SUCCESS) return m_StatusCode; } return GPIB_SUCCESS; } I tried putting a small Sleep() delay (10-20 ms) at the end of the inner loop, and to my surprise it caused the error to show up earlier rather than later. 10 ms caused the loop to error out at 44,1 and 20 ms was even sooner. I've already eliminated faulty cabling or the instrument as the culprit. This same type of sequence works without any error on a higher end signal generator, so I'm tempted to chalk this up to a bug in the instrument's firmware.

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  • Clean up upon the kill signal

    - by Begui
    How do you handle clean up when the program receives a kill signal? For instance, there is an application I connect to that wants any third party app (my app) to send a finish command. What is the best say to send that finish command when my app has been destroyed with a kill -9?

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  • sigsetjmp and siglongjmp inside signal handler

    - by EpsilonVector
    How do I: sigsetjmp inside the handler and then return from the handler such that the signal will be unmasked once I siglongjmp back to this point? In pseudo code this is sort of the function that I have: signal_handler(){ if(sigsetjmp(env[i++])) return; else siglongjmp(env[i]); } It's supposed to be the context switch code for user threads in Linux.

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  • Tracing UNIX signal origins?

    - by jdizzle
    If I have a process that receives signals from other processes, is there a way for me to somehow tell which process (if any) sent a signal? strace lets me trace which signals a process has received, but doesn't allow me to trace who issued them.

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  • emit signal from thread

    - by Umesha MS
    Hi, I am writing a sample which uses thread to do some background processing. In the thread I am trying to emitting a signal. But it is not coming to slot. While connecting I checked the value of “connect()” function value , it is returning value as true. One thing to notice is in the run method I am not using “exec() “ . Please help me to solve this problem.

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  • add new records using signal in django admin

    - by ganesh
    I've a model called broadcastinfo, It has fields viz.. info,userid...userid is excluded. when i add an new info, my broadcastinfo table should get the records of all userid from user table and the given message. Im trying this via signal.Any idea is highly appreciated. Thanks

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  • How to gracefully handle the SIGKILL signal in Java

    - by Begui
    How do you handle clean up when the program receives a kill signal? For instance, there is an application I connect to that wants any third party app (my app) to send a finish command. What is the best say to send that finish command when my app has been destroyed with a kill -9?

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  • Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

    - by MarkPearl
    After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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  • Any patent issue if I want to call my classes "signal/slot" as in Qt?

    - by user129506
    I need to code a signal-like mechanism and I was thinking of using the same "slot" and "signal" terms to indicate the signal and the function that needs to be called. Since this is a commercial application I'd like to know if there might be any issue with using these names, e.g. if Qt has some sort of patent on them (I searched around but couldn't find it). I believe this is a stupid question since patenting a class name would be moronic, to say the least.. but anyway... To add some detail: my code is ENTIRELY different and has NOTHING TO DO with Qt except the above. I don't use moc or any Qt class.

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  • Memory leak problem. iPhone SDK

    - by user326375
    Hello, i've got a problem, i cannot solve it, just recieving error: Program received signal: “0”. The Debugger has exited due to signal 10 (SIGBUS).The Debugger has exited due to signal 10 (SIGBUS). Here is some method, if i comment it out, problem goes aways - (void)loadTexture { const int num_tex = 10; glGenTextures(num_tex, &textures[0]); //TEXTURE #1 textureImage[0] = [UIImage imageNamed:@"wonder.jpg"].CGImage; //TEXTURE #2 textureImage[1] = [UIImage imageNamed:@"wonder.jpg"].CGImage; //TEXTURE #3 textureImage[2] = [UIImage imageNamed:@"wall_eyes.jpg"].CGImage; //TEXTURE #4 textureImage[3] = [UIImage imageNamed:@"wall.jpg"].CGImage; //TEXTURE #5 textureImage[4] = [UIImage imageNamed:@"books.jpg"].CGImage; //TEXTURE #6 textureImage[5] = [UIImage imageNamed:@"bush.jpg"].CGImage; //TEXTURE #7 textureImage[6] = [UIImage imageNamed:@"mushroom.jpg"].CGImage; //TEXTURE #8 textureImage[7] = [UIImage imageNamed:@"roots.jpg"].CGImage; //TEXTURE #9 textureImage[8] = [UIImage imageNamed:@"roots.jpg"].CGImage; //TEXTURE #10 textureImage[9] = [UIImage imageNamed:@"clean.jpg"].CGImage; for(int i=0; i<num_tex; i++) { NSInteger texWidth = CGImageGetWidth(textureImage[i]); NSInteger texHeight = CGImageGetHeight(textureImage[i]); GLubyte *textureData = (GLubyte *)malloc(texWidth * texHeight * 4); CGContextRef textureContext = CGBitmapContextCreate(textureData, texWidth, texHeight, 8, texWidth * 4, CGImageGetColorSpace(textureImage[i]), kCGImageAlphaPremultipliedLast); CGContextDrawImage(textureContext, CGRectMake(0.0, 0.0, (float)texWidth, (float)texHeight), textureImage[i]); CGContextRelease(textureContext); glBindTexture(GL_TEXTURE_2D, textures[i]); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); free(textureData); } } anyone can help me with releasing/deleting objects in this method? Thanks.

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  • Improve wireless performance

    - by djechelon
    Hello, I have a Trust Speedshare Turbo Pro router, which is running on channel 6. I found that the wireless signal (and network performance) dramatically drops from my PDA (I can barely attach to the network, even if I set the PDA's energy settings to maximum wireless performance) when I even exit my room, and I don't have shielded walls or something like that. I can't even stream a SD video from my desktop (connected via LAN) to my laptop using WiFi, while via LAN it works fine. I read that changing router's channel could improve performance due to interference reducing. I found that almost all wireless networks around here run on channels 6 and 11. I tried to go to my router's settings page to change channel, but I found that the combo box only allows me to select 6!! I'm not sure, but I may have been able in the past to change channel, though not to all of the available channels. A few minutes ago I tried a firmware upgrade, but it didn't solve my problem. My question is Is it possible that my router is someway locked to its channel? I bought it on my own, I didn't receive it from my ISP Apart from boosting the antenna power to the maximum (which, by the way, increases the EM radiation my and my family's bodies absorb 24/7 and is little more environment-unfriendly), do you have any tips on getting high quality transmission up to 5 metres from the antenna? Thank you

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  • how to clear stack after stack overflow signal occur

    - by user353573
    In pthread, After reaching yellow zone in stack, signal handler stop the recursive function by making it return however, we can only continue to use extra area in yellow zone, how to clear the rubbish before the yellow zone in the thread stack ? (Copied from "answers"): #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <setjmp.h> #include <sys/mman.h> #include <unistd.h> #include <assert.h> #include <sys/resource.h> #define ALT_STACK_SIZE (64*1024) #define YELLOW_ZONE_PAGES (1) typedef struct { size_t stack_size; char* stack_pointer; char* red_zone_boundary; char* yellow_zone_boundary; sigjmp_buf return_point; size_t red_zone_size; } ThreadInfo; static pthread_key_t thread_info_key; static struct sigaction newAct, oldAct; bool gofromyellow = false; int call_times = 0; static void main_routine(){ // make it overflow if(gofromyellow == true) { printf("return from yellow zone, called %d times\n", call_times); return; } else { call_times = call_times + 1; main_routine(); gofromyellow = true; } } // red zone management static void stackoverflow_routine(){ fprintf(stderr, "stack overflow error.\n"); fflush(stderr); } // yellow zone management static void yellow_zone_hook(){ fprintf(stderr, "exceed yellow zone.\n"); fflush(stderr); } static int get_stack_info(void** stackaddr, size_t* stacksize){ int ret = -1; pthread_attr_t attr; pthread_attr_init(&attr); if(pthread_getattr_np(pthread_self(), &attr) == 0){ ret = pthread_attr_getstack(&attr, stackaddr, stacksize); } pthread_attr_destroy(&attr); return ret; } static int is_in_stack(const ThreadInfo* tinfo, char* pointer){ return (tinfo->stack_pointer <= pointer) && (pointer < tinfo->stack_pointer + tinfo->stack_size); } static int is_in_red_zone(const ThreadInfo* tinfo, char* pointer){ if(tinfo->red_zone_boundary){ return (tinfo->stack_pointer <= pointer) && (pointer < tinfo->red_zone_boundary); } } static int is_in_yellow_zone(const ThreadInfo* tinfo, char* pointer){ if(tinfo->yellow_zone_boundary){ return (tinfo->red_zone_boundary <= pointer) && (pointer < tinfo->yellow_zone_boundary); } } static void set_yellow_zone(ThreadInfo* tinfo){ int pagesize = sysconf(_SC_PAGE_SIZE); assert(pagesize > 0); tinfo->yellow_zone_boundary = tinfo->red_zone_boundary + pagesize * YELLOW_ZONE_PAGES; mprotect(tinfo->red_zone_boundary, pagesize * YELLOW_ZONE_PAGES, PROT_NONE); } static void reset_yellow_zone(ThreadInfo* tinfo){ size_t pagesize = tinfo->yellow_zone_boundary - tinfo->red_zone_boundary; if(mmap(tinfo->red_zone_boundary, pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0) == 0){ perror("mmap failed"), exit(1); } mprotect(tinfo->red_zone_boundary, pagesize, PROT_READ | PROT_WRITE); tinfo->yellow_zone_boundary = 0; } static void signal_handler(int sig, siginfo_t* sig_info, void* sig_data){ if(sig == SIGSEGV){ ThreadInfo* tinfo = (ThreadInfo*) pthread_getspecific(thread_info_key); char* fault_address = (char*) sig_info->si_addr; if(is_in_stack(tinfo, fault_address)){ if(is_in_red_zone(tinfo, fault_address)){ siglongjmp(tinfo->return_point, 1); }else if(is_in_yellow_zone(tinfo, fault_address)){ reset_yellow_zone(tinfo); yellow_zone_hook(); gofromyellow = true; return; } else { //inside stack not related overflow SEGV happen } } } } static void register_application_info(){ pthread_key_create(&thread_info_key, NULL); sigemptyset(&newAct.sa_mask); sigaddset(&newAct.sa_mask, SIGSEGV); newAct.sa_sigaction = signal_handler; newAct.sa_flags = SA_SIGINFO | SA_RESTART | SA_ONSTACK; sigaction(SIGSEGV, &newAct, &oldAct); } static void register_thread_info(ThreadInfo* tinfo){ stack_t ss; pthread_setspecific(thread_info_key, tinfo); get_stack_info((void**)&tinfo->stack_pointer, &tinfo->stack_size); printf("stack size %d mb\n", tinfo->stack_size/1024/1024 ); tinfo->red_zone_boundary = tinfo->stack_pointer + tinfo->red_zone_size; set_yellow_zone(tinfo); ss.ss_sp = (char*)malloc(ALT_STACK_SIZE); ss.ss_size = ALT_STACK_SIZE; ss.ss_flags = 0; sigaltstack(&ss, NULL); } static void* thread_routine(void* p){ ThreadInfo* tinfo = (ThreadInfo*)p; register_thread_info(tinfo); if(sigsetjmp(tinfo->return_point, 1) == 0){ main_routine(); } else { stackoverflow_routine(); } free(tinfo); printf("after tinfo, end thread\n"); return 0; } int main(int argc, char** argv){ register_application_info(); if( argc == 2 ){ int stacksize = atoi(argv[1]); pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 1024 * 1024 * stacksize); { pthread_t pid0; ThreadInfo* tinfo = (ThreadInfo*)calloc(1, sizeof(ThreadInfo)); pthread_attr_getguardsize(&attr, &tinfo->red_zone_size); pthread_create(&pid0, &attr, thread_routine, tinfo); pthread_join(pid0, NULL); } } else { printf("Usage: %s stacksize(mb)\n", argv[0]); } return 0; } C language in linux, ubuntu

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  • MPI signal handling

    - by Seth Johnson
    When using mpirun, is it possible to catch signals (for example, the SIGINT generated by ^C) in the code being run? For example, I'm running a parallelized python code. I can except KeyboardInterrupt to catch those errors when running python blah.py by itself, but I can't when doing mpirun -np 1 python blah.py. Does anyone have a suggestion? Even finding how to catch signals in a C or C++ compiled program would be a helpful start. If I send a signal to the spawned Python processes, they can handle the signals properly; however, signals sent to the parent orterun process (i.e. from exceeding wall time on a cluster, or pressing control-C in a terminal) will kill everything immediately.

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  • wxPython: Sending a signal to several widgets

    - by cool-RR
    I am not even sure how to ask this question. I want something that is like the wxPython event system, but a bit different. I'll try to explain. When there is a certain change in my program (a "tree change", never mind what that is,) I want to send a signal to all the widgets in my program, notifying them that a "tree change" has occurred, and they should change their display in response. How do I do this? It sounds a little bit like wxPython events, but not really, since events don't spread to all widgets, as far as I know. What would be a good way to do this?

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  • How to properly siglongjmp out of signal handler?

    - by EpsilonVector
    Suppose I have the following code: In order to implement a context switch I activate ualarm and when it jumps to the handler it setjmp's the current context, and longjmps to the next, expecting to eventually return to the alarm handler and longjmped back into this context (the contexts are cycled through in a Round Robin). For this I need to keep SIGALRM unblocked in between alarm_handlers. I came up with the following code, which doesn't seem to work. What's wrong with it and what is the right way to do this? void alarm_handler(){ if(sigsetjmp(toc->threads[toc->RR_pointer].env, 0)){ ualarm(200, 0); signal(SIGALRM, alarm_handler); return; } get_next_context_number(toc->RR_pointer); //is a macro for (j=0; j<10; j++) printf("ALARM HANDLER\n"); siglongjmp(toc->threads[toc->RR_pointer].env, 1); }

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  • Ruby Multithreading: making one thread wait for a signal from another

    - by Peter
    In Ruby, I want to have two threads running at the same time, and want the background thread to periodically signal the foreground thread. How do I get the foreground thread to block until the background thread says 'go'? I can think of a few ways to do it, but am after the most appropriate, idiomatic Ruby method. In code: loop do # background, thread 1 sleep 3 receive_input # tell foreground input is ready # <-- how do I do this? end and loop do # foreground, thread 2 wait_for_signal_from_background # <-- how do I do this? do_something end

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