I'm using spdlog and trying to create a logger object to be shared between multiple source files. However, whenever I use the built in spdlog::get() function it results in a segmentation fault error.
foo.cpp
#include "bar.h"
#include "spdlog/spdlog.h"
#include "spdlog/sinks/stdout_color_sinks.h"
#include "spdlog/sinks/basic_file_sink.h"
int main()
{
// Create log sinks w/ destinations
auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
auto file_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("logs/myLogFile.log", true);
// Format logging statements
console_sink->set_pattern("[%Y-%m-%d %H:%M:%S] [%n] [%^%l%$] %v");
file_sink->set_pattern("[%Y-%m-%d %H:%M:%S.%e] [Thread:%t] [%n] [%l] %v");
// Create multi-sink logger object
spdlog::logger myLogger("myLogger", {console_sink, file_sink});
myLogger.info("Hello World! - foo.cpp");
loggerTest();
return 0;
}
bar.h
#ifndef BAR_H
#define BAR_H
void loggerTest();
#endif
bar.cpp
#include "bar.h"
#include "spdlog/spdlog.h"
void loggerTest()
{
std::shared_ptr<spdlog::logger> myLogger = spdlog::get("myLogger");
myLogger->info("Hello World! - bar.cpp");
}
Why am I getting a segmentation fault error? How do I setup a logger to be shared between multiple source files?
Related
So I've done extensive googling and searching on StackOverflow and am unable to find a solution despite several answers with this exact issue.
I am trying to create a test class in an external file called Fpc5.cpp
It's contents are:
Fpc5.cpp
#include "stdafx.h"
#include "Fpc5.h";
#include <iostream>
using std::cout;
class Fpc5 {
int bar;
public:
void testMethod();
};
void Fpc5::testMethod() {
cout << "Hey it worked! ";
}
and my main .cpp file:
Test.cpp
// Test.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "iostream"
//#include "Fpc5.cpp"
#include "Fpc5.h";
using std::cout;
using std::cin;
using std::endl;
int main()
{
cout << "Hello" << endl;
Fpc5 testObj;
testObj.testMethod();
system("pause");
return 0;
}
all the answers I've read indicate this is caused becaused I used to be including the class in the main file itself which is why I created a header file
Fpc5.h
#pragma once
void testMethod();
This changed the error, but still did not fix the issue. Currently my Test.cpp does not recognize a Fpc5 class. I've also tried adding the Fpc5.cpp and Fpc5.h in stdafx.h and that still does not resolve the issue.
stdafx.h
// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently, but
// are changed infrequently
//
#pragma once
#include "targetver.h"
#include <stdio.h>
#include <tchar.h>
// TODO: reference additional headers your program requires here
//#include "Fpc5.cpp"
#include "Fpc5.h"
I'm sure this a simple syntax/conceptual understanding error, but I'm quite new to c++ and am not sure what is wrong.
This is definition of your class and it must be in Fpc5.h
class Fpc5 {
int bar;
public:
void testMethod();
};
Then, you have Fpc5.cpp where you implement methods of the class:
#include "Fpc5.h" // Compiler needs class definition to compile this file!
void Fpc5::testMethod()
{
}
And then you can use Fpc5 class in Test.cpp
#include "Fpc5.h"
int main()
{
Fpc5 foo;
foo.testMethod();
return 0;
}
As an alternative you can pack everything into Test.cpp
Move the definition of your class:
class Fpc5 {
int bar;
public:
void testMethod();
};
to the header file, "Fpc5.h".
Implement the methods to "Fpc5.cpp".
I am unsure about the use of separate files for classes. How do I make functions inside the classes? Where do I put it?
QuizMain.cpp:
#include "QuizMain.h"
#include <iostream>
#include <string>
using namespace std;
QuizMain::QuizMain()
{
// Hia stackoverflow
}
QuizMain.h file:
#ifndef QUIZMAIN_H
#define QUIZMAIN_H
#include <string>
using namespace std;
class QuizMain
{
public:
QuizMain();
private:
};
#endif // QUIZMAIN_H
Main file:
#include <iostream>
#include <string>
#include "QuizMain.h"
using namespace std;
int main()
{
QuizMain qm;
return 0;
}
How would I make a class and call it correctly?
This is an example:
QuizMain.cpp file:
#include "QuizMain.h"
#include <iostream>
#include <string>
using namespace std;
QuizMain::QuizMain()
{
// Hia stackoverflow
}
void QuizMain::my_new_function(std::string my_name){
std::cout << "Hi " + my_name +"!" << std::endl;
}
QuizMain.h file:
#ifndef QUIZMAIN_H
#define QUIZMAIN_H
#include <string>
class QuizMain
{
public:
QuizMain();
void my_new_function(std::string my_name);
private:
};
#endif // QUIZMAIN_H
Main file:
#include <iostream>
#include <string>
#include "QuizMain.h"
using namespace std;
int main()
{
QuizMain qm;
qm.my_new_function("foo");
return 0;
}
Anyway, there is no point from asking such a question here. You should probably find a good book/resource and learn how to write and use functions.
Normally you have a header file and cpp file. The header file is where you declare your functions and member variables. The cpp file is where you implement your functions.
quizmain.h
// QuizMain.h file
#ifndef QUIZMAIN_H
#define QUIZMAIN_H
#include <string>
class QuizMain
{
public:
QuizMain(int quizScore);
// declare public functions here
private:
int quizScore; // declare private member variables here.
};
#endif // QUIZMAIN_H
cpp file
// QuizMain.cpp file
#include "QuizMain.h"
#include <iostream>
#include <string>
using namespace std;
QuizMain::QuizMain(int quizScore)
{
this.quizScore = quizScore; // init a quiz score
}
main
Call and create a class object like this
QuizMain quiz(95);
It is easy to do.
If you use the IDE project, the IDE set you to use the any file. Like code::block IDE But if you do not use the IDE project it is a little different to use.
You should write the .h file and then,after all writing you should put .cpp file.
Also you can use interface class that works by poiter.
/// .h file and declaration
#ifndef ONE.H
#define ONE.H
class one {
public:
one();
~one();
};
#include "one.cpp"
#endif ONE.H
then:
/// .cpp file and implementation
one::one(){
std::cout<<"constructor one"<<std::endl;
}
one::~one(){
std::cout<<"destructor one"<<std::endl;
}
then :
#include <iostream>
#include "one.h"
int main()
{
one o;
}
output:
constructor one
destructor one
Process returned 0 (0x0) execution time : 0.010 s
Press ENTER to continue.
I have already checked StackOverflow to find the solution to my problem, but I think I might be missing something. I am trying to define a class in a header file (.h) and implement its methods in a cpp file (.cpp), but it does not work.
main.cpp:
#include <iostream>
#include "Message.h"
using namespace std;
int main()
{
Message *t = new (Message);
t->display();
return 0;
}
Message.h:
#ifndef MESSAGE_H_INCLUDED
#define MESSAGE_H_INCLUDED
class Message {
public:
void display();
};
#endif // MESSAGE_H_INCLUDED
Message.cpp:
#include "Message.h"
void Message::display() {
cout << "Hello!";
}
I don't understand why I keep getting the following error
undefined reference to 'Message::display()'
Compile this with the command g++ -std=c++11 Message.cpp main.cpp
I am trying to access C++ function from C program using Visual Studio 2012 IDE. When I am debugging, I am getting the below error in TestCpp.cpp, in Method: helloworld(), in Line: http_client cli( U("http://localhost:55505/api/Notification"));
Unhandled exception at 0x0000000076D23290 (ntdll.dll) in MyTestCLib.exe: 0xC0000005:
Access violation reading location 0x00000621BC90B128.
Please find the code snippet below.
MyTestCLib.c
#include <ctype.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <my_global.h>
#include <mysql.h>
#include <m_ctype.h>
#include "TestCpp.h"
int main()
{
helloWorld();
return 0;
}
TestCpp.h
#ifndef HEADER_FILE
#define HEADER_FILE
#ifdef __cplusplus
extern "C" {
#endif
void helloWorld();
#ifdef __cplusplus
}
#endif
#endif
TestCpp.cpp
// Calling REST API from C++ using C++ REST API SDK
#include <cpprest/http_client.h>
#include <cpprest/filestream.h>
#include <iostream>
#include "TestCpp.h"
using namespace utility; // Common utilities like string conversions
using namespace web; // Common features like URIs.
using namespace web::http; // Common HTTP functionality
using namespace web::http::client; // HTTP client features
using namespace concurrency::streams; // Asynchronous streams
using namespace std;
void helloWorld()
{
http_client cli( U("http://localhost:55505/api/Notification") );
ostringstream_t uri;
uri << U("/PostNotification");
json::value bodyarray = json::value::array();
json::value body = json::value::object();
body[U("TicketNumber")] = json::value::string( U("25868") );
body[U("NotificationMessage")] = json::value::string( U("Test Notification Message") );
bodyarray[0] = body;
http_response response = cli.request( methods::POST, uri.str(), bodyarray.serialize(), U("application/json") ).get();
if ( response.status_code() == status_codes::OK &&
response.headers().content_type() == U("application/json") )
{
json::value json_response = response.extract_json().get();
ucout << json_response.serialize() << endl;
}
else
{
ucout << response.to_string() << endl;
getchar();
}
}
From MyTestCLib.c You call helloWorld declared as C, but complier creates only C++ function version. This call faill because C++ function uses CPU registry and stack different way. There is simple solution. Create C version of function with different name.
TestCpp.h
#ifdef __cplusplus
void helloWorld();
#else
void c_helloWorld();
#endif
TestCpp.cpp
#include "TestCpp.h"
void helloWorld(void)
{
/* cpp code */
}
extern "C" {
void c_helloWorld(void) // C version of helloWorld
{
helloWorld(); // call cpp helloWorld
}
}
Source file with .c extension is complied by C-Compiler. It can't call C++ function. But in .cpp file complied by C++ Compler you can create C function. This "C" function (c_helloWorld) in compiled by C++ compiler and can be called from C-Complier. It can also call C++ function.
Recently I've been learning how to create methods within classes so that I only have to write a method once and for each of that class I instantiate I can call the one method and it will work only on the variables of the object that called it, I know how to do this when only using main.cpp and no headers however I am confused on how I should be writing this when I use a class header and cpp.
I have a sample of code similar to what I want to achieve:
#include <iostream>
using namespace::std;
class Object
{
public:
int stuff;
void manageStuff();
Object();
};
void Object::manageStuff()
{
stuff++;
}
Object::Object() : stuff(0) {}
Object object1, object2;
int main() {
for (int i = 0; i < 10; i++)
{
object1.manageStuff();
object2.manageStuff();
cout << object1.stuff << "\n";
cout << object2.stuff << "\n";
}
}
This works fine and allows me to have two instances of Object and a method that works independently for each instance, this is my current project:
main.cpp:
#include <iostream>
#include "Test.h"
using namespace std;
int main()
{
Test test;
for (int i = 0; i < 10; i++)
{
test.count(); // Here's my error "undefined reference to Test::count"
}
return 0;
}
Test.cpp
#include <iostream>
#include "Test.h"
using namespace std;
Test::Test()
{
//ctor
}
Test::~Test()
{
//dtor
}
Test.h
#include <iostream>
#ifndef TEST_H
#define TEST_H
class Test
{
public:
Test();
virtual ~Test();
void count();
int counter();
};
#endif // TEST_H
and finally TestFunctions.h
#include <iostream>
#include "Test.h"
#ifndef TESTFUNCTIONS_H_INCLUDED
#define TESTFUNCTIONS_H_INCLUDED
void Test::count()
{
Test::counter++;
std::cout << Test::counter;
}
#endif // TESTFUNCTIONS_H_INCLUDED
I'm sure that there will be something that's very obviously wrong to a more seasoned programmer and I'm about to look a bit thick but any help would be greatly appreciated
Thanks!
I would suggest getting rid of TestFunctions.h, and adding the implementation of Test::count() to Test.cpp. Currently, the TestFunctions.h header is not included anywhere, so you have no access to the definition from main.
You defined (i.e. implemented) Test::count() in a header file (TestFunctions.h), but you never included it anywhere so the code there is not compiled.
You should change it to be in a .cpp file, compile it and link it with the other source files. There's no reason why not to place it in Test.cpp.
Rename TestFunctions.h into TestFunctions.cpp, make it compiled same way as main.cpp and linked.
Alternatively, include TestFunctions.h somewhere, e.g. main.cpp