C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Problem with writing my own header file...          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message WW Guest Posted: Sat Sep 27, 2003 10:20 am    Post subject: Re: [OT]Problem with writing my own header file... Markus wrote: Quote: Hi, Well, I'm still a newbie to C++, so excuse my maybe (probably???) stupid question...btw, I use gcc 2.95.2. Here are my (test) funtions: mainfunc.cpp: #include using namesapce std; Quote: #include "func1.h" //so it looks in the same dir, right? int main(){ int a=42; func1(a); } func1.cpp: #include using namesapce std; Quote: #include "func1.h" /* I read you should also include it here... */ void func1(int i) { cout << i << endl; } func1.h: void func1(int i); My Problem is that when I try to compile it, it gives me an "undefined reference to 'func1(int)' error and I don't know how to get rid of it. I tried to put the files everywhere, like in the "include"-folder or others folders that I set with path. What is my mistake??? Thank you in advance, I really appreciate it! You need to LINK func1.o into your executable! Please get a gcc/g++ manual and read about it. It is _using_ your compiler and not about the language so - strictly speaking - it is off topic here. Byt I am pretty sure that a million tutorials exist out there for gcc/g++. -- WW aka Attila Back to top Markus Guest Posted: Sat Sep 27, 2003 10:22 am    Post subject: Problem with writing my own header file... Hi, Well, I'm still a newbie to C++, so excuse my maybe (probably???) stupid question...btw, I use gcc 2.95.2. Here are my (test) funtions: mainfunc.cpp: #include <iostream> #include "func1.h" //so it looks in the same dir, right? int main(){ int a=42; func1(a); } func1.cpp: #include <iostream> #include "func1.h" /* I read you should also include it here... */ void func1(int i) { cout << i << endl; } func1.h: void func1(int i); My Problem is that when I try to compile it, it gives me an "undefined reference to 'func1(int)' error and I don't know how to get rid of it. I tried to put the files everywhere, like in the "include"-folder or others folders that I set with path. What is my mistake??? Thank you in advance, I really appreciate it! Regards Markus Back to top Agent Mulder Guest Posted: Sat Sep 27, 2003 8:21 pm    Post subject: Re: Problem with writing my own header file... <Markus> Quote: My Problem is that when I try to compile it, it gives me an "undefined reference to 'func1(int)' error and I don't know how to get rid of it. I tried to put the files everywhere, like in the "include"-folder or others folders that I set with path. What is my mistake??? Thank you in advance, I really appreciate it! / JT> I really don't want to define all the hundreds of error message strings in JT> every .cpp file. What do i wrong? JT> JT> Any hint appreciated. You can use this very simple scheme if you like: //file First.cpp class First{public:First(){cout<<"phew";}; //file Second.cpp class Second:public First{public:Second():First(){cout<<"gosh";}}; //file Third.cpp class Third { public: vector First f; Second s; Third(){cout<<"well-well";} }; //file main.cpp #include #include <vector.h> #include "First.cpp" #include "Second.cpp" #include "Third.cpp" int main(int argc,char**argv) { First f; Second s; Third t; return 0; } All the includes are summarized in file main.cpp. The only file that gets compiled is main.cpp and consequently all other cpp files. What actually happens is that the precompiler expands all the included files into main.cpp and then that expanded file is compiled. So no complicated makefiles and no double includes, at the cost of longer compilation time. Stale .obj files can be a serious source of bugs. With this approach you are sure to always work on your most recent version. -X Back to top Frank Schmitt Guest Posted: Mon Sep 29, 2003 7:05 am    Post subject: Re: Problem with writing my own header file... "Markus" <Markus.Eckelt (AT) nospam (DOT) de> writes: Quote: Hi, Well, I'm still a newbie to C++, so excuse my maybe (probably???) stupid question...btw, I use gcc 2.95.2. Here are my (test) funtions: mainfunc.cpp: #include #include "func1.h" //so it looks in the same dir, right? int main(){ int a=42; func1(a); } func1.cpp: #include #include "func1.h" /* I read you should also include it here... */ void func1(int i) { cout << i << endl; } func1.h: void func1(int i); My Problem is that when I try to compile it, it gives me an "undefined reference to 'func1(int)' error and I don't know how to get rid of it. Undefined reference means that the *linker* could not find your function - you have to link in every source file in your project. compile it with g++ -Wall -ansi -pedantic mainfunc.cpp func1.cpp and it should work. HTH & kind regards frank -- Frank Schmitt 4SC AG phone: +49 89 700763-0 e-mail: frankNO DOT SPAMschmitt AT 4sc DOT com Back to top Frank Schmitt Guest Posted: Tue Sep 30, 2003 12:03 pm    Post subject: Re: Problem with writing my own header file... "Markus" <Markus.Eckelt (AT) nospam (DOT) de> writes: Quote: "Frank Schmitt" <invalid (AT) seesignature (DOT) info> wrote in message news:4cwubsgjmr.fsf (AT) scxw21 (DOT) 4sc... Undefined reference means that the *linker* could not find your function - you have to link in every source file in your project. compile it with g++ -Wall -ansi -pedantic mainfunc.cpp func1.cpp and it should work. HTH & kind regards frank It compiled alright but did not create an executable??? Usually I use Textpad, so I don't really know the command settings. WW said there should be millions of tutorials about that, couldn't find one so far but I'll keep looking. Thanks! I find this hard to believe - searching for "gcc tutorial" on google turns up zillions of links, among them http://users.actcom.co.il/~choo/lupg/tutorials/c-on-unix/c-on-unix.html#running_the_exe regards frank -- Frank Schmitt 4SC AG phone: +49 89 700763-0 e-mail: frankNO DOT SPAMschmitt AT 4sc DOT com Back to top Markus Guest Posted: Tue Sep 30, 2003 12:07 pm    Post subject: Re: Problem with writing my own header file... "Agent Mulder" <mbmulder_remove_this_ (AT) home (DOT) nl> wrote Quote: You can use this very simple scheme if you like: //file First.cpp class First{public:First(){cout<<"phew";}; //file Second.cpp class Second:public First{public:Second():First(){cout<<"gosh";}}; //file Third.cpp class Third { public: vector First f; Second s; Third(){cout<<"well-well";} }; //file main.cpp #include #include #include "First.cpp" #include "Second.cpp" #include "Third.cpp" int main(int argc,char**argv) { First f; Second s; Third t; return 0; } All the includes are summarized in file main.cpp. The only file that gets compiled is main.cpp and consequently all other cpp files. What actually happens is that the precompiler expands all the included files into main.cpp and then that expanded file is compiled. So no complicated makefiles and no double includes, at the cost of longer compilation time. Stale .obj files can be a serious source of bugs. With this approach you are sure to always work on your most recent version. -X Thank you! Yes, your solution does work, even though it is not the approach I was using. This way I don't need the header file at all, but the way I see it (from my newbie point of view), I can't pass on values that easily, right? Back to top Markus Guest Posted: Tue Sep 30, 2003 12:17 pm    Post subject: Re: Problem with writing my own header file... "Frank Schmitt" <invalid (AT) seesignature (DOT) info> wrote Quote: Undefined reference means that the *linker* could not find your function - you have to link in every source file in your project. compile it with g++ -Wall -ansi -pedantic mainfunc.cpp func1.cpp and it should work. HTH & kind regards frank It compiled alright but did not create an executable??? Usually I use Textpad, so I don't really know the command settings. WW said there should be millions of tutorials about that, couldn't find one so far but I'll keep looking. Thanks! Back to top Markus Guest Posted: Tue Sep 30, 2003 2:38 pm    Post subject: Re: Problem with writing my own header file... "Frank Schmitt" <invalid (AT) seesignature (DOT) info> wrote Quote: I find this hard to believe - searching for "gcc tutorial" on google turns up zillions of links, among them http://users.actcom.co.il/~choo/lupg/tutorials/c-on-unix/c-on-unix.html#running_the_exe regards frank Oh, no - you're absolutly right! There are plenty of tutorials out there, what I meant was a tutorial for gcc in combination with textpad. I got it as far as compiling and all, but I don't know how to do it with including other funtions... The class solutions works, but I'd believe there should be an easier way. But on the other hand, I don't have a clue, so I'm probably wrong anyways. Thank you again for the reply, though. ;-) Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         C++Talk.NET Forum Index -> C++ language (comp.lang.c++) All times are GMT Page 1 of 1   Jump to: Select a forum C/C++----------------C LanguageC Language (Moderated)C++ Language (Moderated)C++ language (comp.lang.c++)C++ language, library and standards Non-English C/C++ Newsgroups----------------C++ (German)C++ (French)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.