Problems compiling sigc++ example

Hi,

i'm trying to get sigc++ working with the example files from the tutorial of libsigc++;
http://libsigc.sourceforge.net/libsi...html#id2446517

AlienDetector.h

Code:

---

#include <iostream>
#include "sigc++/object.h"
#include <string>
#include "sigc++/signal.h"

class AlienDetector
{
public:
    AlienDetector();

    void run();

    sigc::signal<void> signal_detected;
};

---

AlienDetector.cc

Code:

---

#include "AlienDetector.h"

void warn_people()
{
    cout << "There are aliens in the carpark!" << endl;
}

int main()
{
    AlienDetector mydetector;
    mydetector.signal_detected.connect( sigc::ptr_fun(warn_people) );

    mydetector.run();

    return 0;
}

---

Compileline:

Code:

---

g++ -Wall AlienDetector.cc -o AlienDetector.o -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -lsigc-2.0

---

Error:

Code:

---

/tmp/ccBPmiQJ.o: In function `main':AlienDetector.cc:(.text+0x50): undefined reference to `AlienDetector::AlienDetector()'
:AlienDetector.cc:(.text+0xcb): undefined reference to `AlienDetector::run()'
collect2: ld returned 1 exit status

---

In the tutorial the compileline is using pkconfig inside, which i can't use in the project I want to use sigc with. So i wrote a compileline myself, which should work in my opinion.

Thanks for the help
Hork83

You never implemented the constructor and run() function inside AlienDetector, so the link can't link to their definitions.

i added to AlienDetector.cc

Code:

---

AlienDetector(){}
void run(){
signal_detected();
}

---

Now coming up with the compileerrors

Code:

---

AlienDetector.cc:3: error: expected unqualified-id before ‘)’ token
AlienDetector.cc: In function ‘void run()’:
AlienDetector.cc:5: error: ‘signal_detected’ was not declared in this scope

---

Thats the line where i wrote AlienDetector(){}
Used same compileline as stated above.

Thanks for help

When defining class member functions, you have to specify that they belong to the class, so you would add AlienDetector:: in front of the function names in the cc file.

Ok, i added these...
AlienDetector.h

Code:

---


#include <iostream>
#include "sigc++/object.h"
#include <string>
#include "sigc++/signal.h"

using namespace std;

class AlienDetector : public SigC::Object
{
public:
        AlienDetector::AlienDetector();

    void AlienDetector::run();
        void AlienDetector::warn_people();
        AlienDetector::sigc::signal<void> signal_detected;
};

---

AlienDetector.cc

Code:

---

#include "AlienDetector.h"

AlienDetector::AlienDetector(){}
void AlienDetector::run(){
signal_detected();
}

void AlienDetector::warn_people()
{
    cout << "There are aliens in the carpark!" << endl;
}

int main()
{
    AlienDetector mydetector;
    mydetector.signal_detected.connect( sigc::ptr_fun(warn_people) );

    mydetector.run();

    return 0;
}

---

i get now the following errors, that seems to say that the signal isn't properly declared.

Code:

---

AlienDetector.h:16: error: ‘class AlienDetector::sigc’ has not been declared
AlienDetector.h:16: error: ISO C++ forbids declaration of ‘signal’ with no type
AlienDetector.h:16: error: expected ‘;’ before ‘<’ token
AlienDetector.cc: In member function ‘void AlienDetector::run()’:
AlienDetector.cc:5: error: ‘signal_detected’ was not declared in this scope
AlienDetector.cc: In function ‘int main()’:
AlienDetector.cc:16: error: ‘class AlienDetector’ has no member named ‘signal_detected’
AlienDetector.cc:16: error: ‘warn_people’ was not declared in this scope

---

Whats wrong now?

Thanks
Hork83

As I said, you would need to add AlienDetector:: in front of the function names in the cc file. You also added it in front of the names in the .h file, which is not what you want. Remove all the AlienDetector:: in the h file and try again. Your cc file looks fine now.