I'm new to C++ and ecplice and they are definitely giving my a hard time :)
I'm tring to write simple application that includes main project with refernces to other project
i wrote the following file in shared project:
#ifndef MANAGEDLOG_H_
#define MANAGEDLOG_H_
#include string
#include iostream
#include fstream
using namespace std;
class ManagedLog
{
ofstream _fileStream;
public :
ManagedLog::ManagedLog(string path);
ManagedLog::~ManagedLog();
void ManagedLog::WriteInfoLog(string message,string stackTrace);
};
#endif /* MANAGEDLOG_H_ */
/*
* ManagedLog.cpp
*
* Created on: 18/06/2010
* Author: Eran
*/
#include "ManagedLog.h"
#include iostream
#include fstream
ManagedLog::ManagedLog(string path)
{
_path=path;
}
ManagedLog::~ManagedLog()
{
}
void ManagedLog:: WriteInfoLog(string message,string stackTrace)
{
ofstream myfile;
myfile.open("Eample.txt",ios::app);
myfile.close();
}
and run it in simple hellow world project:
#include "ManagedLog.h"
#include
using namespace std;
int main() {
ManagedLog * log = new ManagedLog("path");
log->WriteInfoLog("test","RunLog/Main");
cout
but I'm getting this error:
*** Build of configuration Debug for project RunLog ****
**** Internal Builder is used for build ****
g++ -ID:\EclipseWorkSpace\LogManager -O0 -g3 -Wall -c -fmessage-length=0 -osrc\RunLog.o ..\src\RunLog.cpp
g++ -LD:\EclipseWorkSpace\LogManager\Release -oRunLog.exe src\RunLog.o
src\RunLog.o: In function `main':
D:/EclipseWorkSpace/RunLog/Debug/../src/RunLog.cpp:13: undefined reference to `ManagedLog::ManagedLog(std::string)'
D:/EclipseWorkSpace/RunLog/Debug/../src/RunLog.cpp:14: undefined reference to `ManagedLog::WriteInfoLog(std::string, std::string)'
collect2: ld returned 1 exit status
Build error occurred, build is stopped
Time consumed: 574 ms.
I added #include "ManagedLog.cpp" and the code work just fine but i guess this is not the right way to do it i read a lot about it but found no answer that i can impliment since i don't understad the term is the reanswers can anybody please help me with the right way to point to other project or dll in this environment?
thanks
Eran
You're not building ManagedLog.cpp. Your compile sequence should look something like this example (simplified for clarity):
compile RunLog.c into RunLog.o
compile ManagedLog.c into ManagedLog.o
link RunLog.o and ManagedLog.o into RunLog.exe
Steps 1 & 2 could be in the other order if you like.
Related
SOLUTION:
Just don't be a noob and run make in the same directory as cmake
Thanks for your answers!
I'm starting with C++ programming and I'm trying to understand how to properly reference a function with .h and .cpp file. I have following files:
\\func.h
#ifndef FUNC_H
#define FUNC_H
int charout(int a, char b);
#endif
\\func.cpp
#include <iostream>
#include "func.h"
using namespace std;
int charout(int a, char b)
{
cout << a;
cout << b;
return 0;
}
\\main.cpp
#include <iostream>
#include "func.h"
using namespace std;
int main ()
{
int a; char b;
cout << "insert an integer " << endl;
cin >> a;
cout << "insert a letter " << endl;
cin >> b;
charout(a,b);
return 0;
}
I am compiling using CMake (with func.h in folder 'include') with following structure:
# Declare the version of the CMake API for forward-compatibility
cmake_minimum_required(VERSION 2.8)
# Declare the name of the CMake Project
project(manual)
# Add the directory to search for header files
include_directories(include)
# Define an executable target
add_executable(main func.cpp main.cpp)
When I try to make main.cpp I am receiving an error:
make main g++ main.cpp -o main /tmp/cctlsXUG.o: In function
main': main.cpp:(.text+0x80): undefined reference tocharout(int,
char)' collect2: error: ld returned 1 exit status : recipe
for target 'main' failed make: *** [main] Error 1
Can you please take a look and let me know where am I doing a mistake?
I will appreciate your feedback. I'm really stuck with this. Cheers!
UPDATE:
OK I managed to compile it with g++ func.cpp main.cpp - o main when I was trying to compile the same code with gcc I got errors of sort undefined reference to std::cout'
I've found out that gcc does not give an access to std of C++. Can I somehow fix my CMake files to use g++ instead of gcc? The project I have to deliver is supposed to have a CMakeLists.txt included.
Finally the last question: why does CMake works fine with function declaration and main in the same file, but not when I split the function into header, cpp and main?
I am a novice programmer in c++, and I am currently getting a compiling error
Undefined symbols for architecture x86_64
Supposedly this originates from how the header files and implementation files are included/coded.
Below is some code that generates the compiling error I am receiving
Main
//Main.cpp
#include <iostream>
#include <string>
#include "Animal.hpp"
using namespace std;
int main(){
Animal myPet;
myPet.shout();
return 0;
}
Header
//Animal.hpp
#ifndef H_Animal
#define H_Animal
using namespace std;
#include <string>
class Animal{
public:
Animal();
void shout();
private:
string roar;
};
#endif
Implementation
//Animal.cpp
#include "Animal.hpp"
#include <string>
Animal::Animal(){
roar = "...";
}
void Animal::shout(){
roar = "ROAR";
cout << roar;
}
This code generates my compiling issue. How would this issue be resolved?
Thanks for your time
EDIT
Undefined symbols for architecture x86_64:
"Animal::shout()", referenced from:
_main in test-5f7f84.o
"Animal::Animal()", referenced from:
_main in test-5f7f84.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
maybe you might want to see an alternative set of your 3 files, where things are a little more "sorted", you know, where things are put at places where they "really" belong to.
So here's the "new" header file ..
//Animal.hpp
#ifndef H_Animal
#define H_Animal
#include <string> // suffices
// Interface.
class Animal {
std::string roar; // private
public:
Animal();
void shout();
};
#endif
then the source file ..
//Animal.cpp
#include "Animal.hpp"
#include <iostream> // suffices
// Constructor.
Animal::Animal()
:
roar("...") // data member initializer
{}
// Member function.
void Animal::shout() {
roar = "ROAR";
std::cout << roar;
}
and the main program ..
//Main.cpp
#include "Animal.hpp"
int main(){
Animal thePet;
thePet.shout(); // outputs: `ROAR'
}
plus a little GNU makefile ..
all: default run
default: Animal.cpp Main.cpp
g++ -o Main.exe Animal.cpp Main.cpp
run:
./Main.exe
clean:
$(RM) *.o *.exe
Kick-off things typing just "make" in your cmd-line. Did you like it? --
Regards, M.
I can only find one error in your code and your compiler should have told you that one.
In Animal.cpp, you are using std::cout but you're not #includeing <iostream>. You #include it in Main.cpp but it is not needed there.
If you (really) want to refer to std::cout as cout in Animal.cpp, you also have to add a using namespace std directive in that file.
The using directive in the header file (Animal.hpp) is evil. Get rid of it and type std::string instead. Putting using directives into headers litters the namespaces of all files that use it.
I also don't understand your intentions with the roar member. What is the point of assigning "..." to it in the constructor and re-assigning "ROAR" to it every time shout is called? Couldn't you do without that variable and simply have
void
Animal::shout()
{
std::cout << "ROAR\n";
}
? I have added a newline because you'd probably want one.
The main issue I was having with this coding project was solved by #JamesMoore.
"#Nicholas Hayden Okay if you have three files, test.cpp(which has main), animal.cpp, and animal.hpp. The command should be g++ animal.cpp test.cpp. You need to compile all source files."
I am currently not using an IDE. So, when I was calling the compiler to compile my main.cpp - It was an issue of compiling the implementation file.
g++ test.cpp
needed to become
g++ test.cpp animal.cpp
This would call the compiler to compile everything the program needed.
This is a minimal program that I made to understand this problem better.
ADT.h
#ifndef ADT_H
#define ADT_H
class ADT {
public:
void print();
};
#endif
ADT.cpp
#include <iostream>
#include "ADT.h"
using namespace std;
void ADT::print()
{
cout << "This program works." << endl;
}
testADT.cpp
#include <iostream>
#include "ADT.h"
using namespace std;
int main(void)
{
ADT sa;
sa.print();
return 0;
}
I compiled it with the vim/minGW compiler my school provided me like so:
g++ testADT.cpp
Which produced the following error:
C:\Users\King\AppData\Local\Tempcc6eoWAP.o:testADT.cpp(.text+0x15 reference to 'ADT::print()'
collect2.exe error: ld returned 1 exit status
Can you explain this error message and indicate the error in my code?
You didn't post the error, but I see that you're missing the semicolon after void print()in the header.
EDIT: That's a linker error. Each source file should be compiled into an object file; then the object files linked:
g++ -c -oADT.o ADT.cpp
g++ -c -otestADT.o testADT.cpp
g++ -oADT ADT.o testADT.o
You can also do it in one line as in michaeltang's answer, but then you can't recompile the sources individually (the 2 step method scales better).
You should also compile ADT.cpp
g++ -o testadt testADT.cpp ADT.cpp
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
What is an undefined reference/unresolved external symbol error and how do I fix it?
I have main.cpp:
#include "censorship_dec.h"
using namespace std;
int main () {
censorship();
return 0;
}
this is my censorship_dec.h:
#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
void censorship();
this is my censorship_mng.cpp:
#include "censorship_dec.h"
using namespace std;
void censorship()
{
cout << "bla bla bla" << endl;
}
I tried to run these files in SSH (Linux), so I wrote: make main, but I got:
g++ main.cpp -o main
/tmp/ccULJJMO.o: In function `main':
main.cpp:(.text+0x71): undefined reference to `censorship()'
collect2: ld returned 1 exit status
make: *** [main] Error 1
please help!
You have to specify the file where censorship is defined.
g++ main.cpp censorship_mng.cpp -o main
You must add censorship_mng.cpp in your compilation command:
g++ main.cpp censorship_mng.cpp -o main
Another solution (if you really don't want change your compile command) is making void censorship(); to a inline function and move it from .cpp to .h.
censorship_dec.h:
#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
inline void censorship()
{
// your code
}
And remove void censorship() from censorship_mng.cpp file.
once your project starts using several source-files to be compiled into a single binary, manual compilations become tedious.
this is usually the time when you start using a build-system, such as a Makefile
a very simple Makefile that uses default build-rules could look like
default: main
# these flags are here only for illustration purposes
CPPFLAGS=-I/usr/include
CFLAGS=-g -O3
CXXFLAGS=-g -O3
LDFLAGS=-lm
# objects (.o files) will be compiled automatically from matching .c and .cpp files
OBJECTS=bar.o bla.o foo.o main.o
# application "main" build-depends on all the objects (and linksthem together)
main: $(OBJECTS)
I am working in c++ /ubuntu.
I have:
libr.hpp
#ifndef LIBR
#define LIBR
#include <string>
using namespace std;
class name
{
public:
name();
~name();
std::string my_name;
std::string method (std::string s);
};
#endif
and
libr.cpp
#include <iostream>
#include <string>
#include <stdlib.h>
#include "libr.hpp"
using namespace std;
name::name()
{
}
std::string name::method(std::string s)
{
return ("YOUR NAME IS: "+s);
}
From these two I've created a libr.a.
In test.cpp:
#include <iostream>
#include <string>
#include <stdlib.h>
#include "libr.hpp"
using namespace std;
int main()
{
name *n = new name();
n->my_name="jack";
cout<<n->method(n->my_name)<<endl;
return 0;
}
I compile with g++ and libr.a. I have an error: "name::name() undefined reference", why?
I would like to mention that I've added in qt creator at qmake the .a. When I compile, I have the error. How can I solve it?
This is a linker error, not a compiler error. It means that you have called but you have not defined the constructor. Your allocation name *n = new name(); calls the constructor.
Since you defined the constructor in your libr.cpp, what this means is that this compilation unit is not making its way into your executable. You mentioned that you are compiling with libr.a. When you compile your libr.cpp the result is a .o file, not a .a file.
You are not linking libr.o into your executable.
What are the steps you're using to compile your "project"?
I performed the following steps and managed to build it with warnings/errors.
g++ -Wall -c libr.cpp
ar -cvq libr.a libr.o
g++ -Wall -o libr main.cpp libr.a
One last thing, if I change the order off the last command, like
g++ -Wall -o libr libr.a main.cpp
I get the following error:
Undefined first referenced
symbol in file
name::name() /tmp/cc4Ro1ZM.o
name::method(std::basic_string<char, std::char_traits<char>, std::allocator<char
> >)/tmp/cc4Ro1ZM.o
ld: fatal: Symbol referencing errors. No output written to libr
collect2: ld returned 1 exit status
in fact ， you needn't define the destructor yourself because the default destructor will be used when the class calling is over.
and in the VS2008，it's all right！