Signal Handling Example (linux C/C++)

Signal Handling Example (linux C/C++)

#include <iostream>

#include <stdio.h>

#include <signal.h>

#include <stdlib.h>

#include <fstream>

class TestClass{

public:

    static void handle_signal(int signal);

};

void TestClass::handle_signal(int signal) {

    //char *signalName;

    std::string signalName = "";

    sigset_t pending;

    switch(signal) {

        case SIGHUP:

            signalName = "SIGHUP";

            break;

        case SIGINT:

            signalName = "SIGINT";

            break;

        case SIGTERM:

            signalName = "SIGTERM";

            break;

        case SIGQUIT:

            signalName = "SIGQUIT";

            break;

        case SIGKILL:

            signalName = "SIGKILL";

            break;

        default:

            printf("Caught unknown signal: %d\n", signal);

            return;

    }

    //실행하고 싶은 함수        

    std::ofstream outFile("./output.txt", std::ios::app);

    printf("Linux signal occurred. signal[%d] : name[%s]\n", signal, signalName.c_str());

    std::string str(std::string("Linux signal occurred. signal[") + std::to_string(signal) + "] signal Name["+ std::string(signalName) + "]");

    outFile << str << std::endl;

    outFile.close();

    //exit(0);

}

int main(int argc, char* arv[]) {

    TestClass *A = new TestClass();

    struct sigaction signalhandler;

    //stack_t sigstk; //for seg.fault

    //if ((sigstk.ss_sp = (char *)//malloc(SIGSTKSZ*2))==NULL) {

    //fprintf(stderr, "can't alloc alt stack\n");

    //}

    //sigstk.ss_size = SIGSTKSZ*2;

    //sigstk.ss_flags = 0;

    //if(sigaltstack(&sigstk, (stack_t *) 0) < 0) {

    //perror("sigaltstack");

    //}

    signalhandler.sa_handler = &TestClass::handle_signal;

    sigemptyset(&signalhandler.sa_mask);

    signalhandler.sa_flags = SA_RESETHAND | SA_ONSTACK;

    sigaction(SIGSEGV, &signalhandler,NULL);

    sigaction(SIGHUP, &signalhandler,NULL);

    sigaction(SIGINT, &signalhandler,NULL);

    sigaction(SIGTERM, &signalhandler,NULL);

    sigaction(SIGQUIT, &signalhandler,NULL);

    sigaction(SIGKILL, &signalhandler,NULL);

    while(1) {

    }

    return 1;

}

#Signal #Signal Handling #Signal Handler #C #C++ #Linux #Embedded

java.net.SocketException: socket failed: EACCES (Permission denied)

App.manifests.Androidmanifest.xml

error:
java.net.SocketException: socket failed: EACCES (Permission denied)

solve:
add : Manifest.xml file

<uses-permissionandroid:name="android.permission.INTERNET"


example:

<?xmlversion="1.0"encoding="utf-8"?>
<manifestxmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidclient">

<uses-permissionandroid:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activityandroid:name=".MainActivity">
<intent-filter>
<actionandroid:name="android.intent.action.MAIN"/>

<categoryandroid:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>

</manifest>



#Android #Java #Permission denied

pure virtual function call (C/C++)

armv7 toolchain Error

error message:
pure virtual function call

solve:
1. Occurs when calling a virtual function from a constructor or destructor.
2. Compiler option did not write -march==armv7-a.

example :
arm-linux-gnueabi-g++ -fno-omit-frame-pointer -march=armv7-a -funwind-tables

#toolchain #embedded #C #C++

Terminate called out an active extension / Aborted (C/C++)

You can build it, but when you run it,

Execute and die when an error occurs.

Error Message:

Terminate called out an active extension

Aborted

Problem

Occurs when coding using "std::thread"

Cause / Solution

When coding using "std::thread", it is caused by not inserting "join"

Example Code:

class TEST {

TEST();

~TEST();

void init();

void end();

std::shared_ptr<std::thread> th = nullptr;

void exec(){}

}

void TEST::init() {

    th = std::make_shared<std::thread>(&TEST::exec , this);

}

void TEST::end() {

if(th != nullptr) {

th->join();

th = nullptr;

}

}

int main() {

Test *t = new TEST();

t->init();

if( t != nullptr ) {

delete t;

t = nullptr;

}

// If this program ends here, an error will occur.

//add code

t->end();

if( t != nullptr ) {

delete t;

t = nullptr;

}

//solved code !

}

#linux #embedded #C #C++ #debug #error #thread #join

wstring to string / string to wstring / utf16 to utf8 / utf8 to utf16(C/C++)

wstring to string / string to wstring

for utf16 parsing error

#include <locale>
#include <codecvt>
#include <string>

std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;

std::string Str_UTF8 = converter.to_bytes(utf16String);

std::wstring wideString_UTF16 = converter.from_bytes(utf8String);

For use, you should modify the bold writing.

#utf16 #utf8 #wstring #string #C #C++ #Embedded #Linux

Function execution time Example. (C++)

std::chrono::system_clock::time_point start = std::chrono::system_clock::now();

myFunc();

std::chrono::duration<double> sec = std::chrono::system_clock::now() - start;

std::cout << "The time taken to perform the function myFunc()  : " << sec.count() << " seconds" << std::endl;

Create Thread Class Example (C++)

The class "std :: thread" exists but has been created for fun.

ThreadClass.h

#pragma once

#include <iostream>

#include <windows.h>

class ThreadClass

{

public:

ThreadClass();

~ThreadClass();

void start();

void stop();

bool isRun();

static DWORD __stdcall run_(void* p);

virtual void run() = 0;

protected:

bool threadRunFlag;

HANDLE m_Thread;

};

ThreadClass.cpp

#include "ThreadClass.h"

//

//\brief constructor,

//\param

//\return

//

ThreadClass::ThreadClass()

{

this->threadRunFlag = false;

}

//

//\brief destructor

//\param

//\return

//

ThreadClass::~ThreadClass()

{

if (this->isRun()) {

this->stop();

}

}

//

//\brief  thread start

//\param

//\return

//

void ThreadClass::start()

{

m_Thread = CreateThread(0, 0, run_, (void*)this, 0, 0);

}

///

///\brief thread end

///\param

///\return

///

void ThreadClass::stop()

{

this->threadRunFlag = false;

// to be...

}

//

//\brief thread status

//\param

//\return

//

bool ThreadClass::isRun()

{

return this->threadRunFlag;

}

//

//\brief thread run

//\param

//\return

//

DWORD __stdcall ThreadClass::run_(void * p)

{

ThreadClass* const THISCLASS = static_cast<ThreadClass*>(p);

THISCLASS->threadRunFlag = true;

THISCLASS->run();

return 0;

}