Why do I get this error message: "undefined reference to `PerformChat(char*, char*, char*, char*, char*)'"

Question

I am trying to compile my program that uses ChatScript libraries. This is my code inside a file named main.cpp :

#include <iostream>

#include "common.h"

using namespace std;


char* output2;
unsigned int InitSystem(int argc,char* argv[]);
void InitStandalone();

int main(int argc, char * argv[])
{
char * userID;
userID="one";


PerformChat("one",NULL,"hi",NULL,output2);

cout<<output2;

    return 0;
}

I tried to include all the ChatScript libraries, also I know the performChat function is within mainSystem.h file that I have included it too(as you can see its in the line 218: https://github.com/bwilcox-1234/ChatScript/blob/master/SRC/mainSystem.h).

But after trying to compile my program by this command :

g++ -std=c++11 main.cpp constructCode.cpp csocket.cpp dictionarySystem.cpp english.cpp evserver.cpp factSystem.cpp functionExecute.cpp infer.cpp jsmn.cpp json.cpp markSystem.cpp mongodb.cpp mysql.cpp os.cpp outputSystem.cpp patternSystem.cpp postgres.cpp privatesrc.cpp scriptCompile.cpp spellcheck.cpp systemVariables.cpp tagger.cpp testing.cpp textUtilities.cpp tokenSystem.cpp topicSystem.cpp userCache.cpp userSystem.cpp variableSystem.cpp -o myprogram

I got many of this errors!!

                                             ^
/tmp/ccuVtYkV.o: In function `main':
main.cpp:(.text+0x36): undefined reference to `PerformChat(char*, char*, char*, char*, char*)'
/tmp/cc6Mhc8u.o: In function `TestIf(char*, FunctionResult&, char*)':
constructCode.cpp:(.text+0x5b): undefined reference to `trace'
constructCode.cpp:(.text+0x203): undefined reference to `trace'
constructCode.cpp:(.text+0x820): undefined reference to `trace'
constructCode.cpp:(.text+0x9d5): undefined reference to `trace'
constructCode.cpp:(.text+0xb62): undefined reference to `trace'
/tmp/cc6Mhc8u.o:constructCode.cpp:(.text+0xbab): more undefined references to `trace' follow
/tmp/cc6Mhc8u.o: In function `HandleIf(char*, char*, FunctionResult&)':
constructCode.cpp:(.text+0xd15): undefined reference to `always'
constructCode.cpp:(.text+0xe75): undefined reference to `trace'
constructCode.cpp:(.text+0x1086): undefined reference to `trace'
constructCode.cpp:(.text+0x11c4): undefined reference to `trace'
/tmp/cc6Mhc8u.o: In function `HandleLoop(char*, char*, FunctionResult&)':
constructCode.cpp:(.text+0x13ab): undefined reference to `trace'
constructCode.cpp:(.text+0x14a7): undefined reference to `trace'
/tmp/cc6Mhc8u.o:constructCode.cpp:(.text+0x298c): more undefined references to `trace' follow
/tmp/ccWaC4y6.o: In function `fillAddr(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned short, sockaddr_in&)':
csocket.cpp:(.text+0x2320): undefined reference to `hostname'
/tmp/ccWaC4y6.o: In function `Client':
csocket.cpp:(.text+0x37bf): undefined reference to `always'
csocket.cpp:(.text+0x3840): undefined reference to `port'
csocket.cpp:(.text+0x389d): undefined reference to `port'
csocket.cpp:(.text+0x3af1): undefined reference to `port'
csocket.cpp:(.text+0x3b4e): undefined reference to `port'
/tmp/ccWaC4y6.o: In function `RegressLoad(void*)':
csocket.cpp:(.text+0x3f96): undefined reference to `revertBuffer'
csocket.cpp:(.text+0x3fcb): undefined reference to `revertBuffer'
csocket.cpp:(.text+0x401c): undefined reference to `revertBuffer'
csocket.cpp:(.text+0x40b9): undefined reference to `port'
/tmp/ccWaC4y6.o: In function `LogChat(long, char*, char*, char*, int, char*, char*)':
csocket.cpp:(.text+0x4559): undefined reference to `version'
/tmp/ccWaC4y6.o: In function `LaunchClient(void*)':
csocket.cpp:(.text+0x4821): undefined reference to `pthread_create'
/tmp/ccWaC4y6.o: In function `InternetServer()':
csocket.cpp:(.text+0x4a01): undefined reference to `pthread_create'
csocket.cpp:(.text+0x4a1f): undefined reference to `pthread_create'
csocket.cpp:(.text+0x4a38): undefined reference to `pthread_join'
/tmp/ccWaC4y6.o: In function `ServerTransferDataToClient()':
csocket.cpp:(.text+0x4a8d): undefined reference to `ourMainOutputBuffer'
/tmp/ccWaC4y6.o: In function `HandleTCPClient(void*)':
csocket.cpp:(.text+0x5454): undefined reference to `outputLength'
/tmp/ccWaC4y6.o: In function `GrabPort()':
csocket.cpp:(.text+0x5777): undefined reference to `interfaceKind[abi:cxx11]'
csocket.cpp:(.text+0x5799): undefined reference to `port'
csocket.cpp:(.text+0x57c7): undefined reference to `port'
csocket.cpp:(.text+0x57d6): undefined reference to `interfaceKind[abi:cxx11]'
/tmp/ccWaC4y6.o: In function `MainChatbotServer()':
csocket.cpp:(.text+0x5940): undefined reference to `quitting'
csocket.cpp:(.text+0x5a7d): undefined reference to `ourMainInputBuffer'
csocket.cpp:(.text+0x5a83): undefined reference to `ourMainInputBuffer'
csocket.cpp:(.text+0x5a8e): undefined reference to `ourMainInputBuffer'
csocket.cpp:(.text+0x5aa1): undefined reference to `ourMainInputBuffer'
csocket.cpp:(.text+0x5afa): undefined reference to `ourMainInputBuffer'
csocket.cpp:(.text+0x5b1b): undefined reference to `ourMainOutputBuffer'
csocket.cpp:(.text+0x5b3b): undefined reference to `ourMainInputBuffer'
csocket.cpp:(.text+0x5b43): undefined reference to `PerformChat(char*, char*, char*, char*, char*)'
csocket.cpp:(.text+0x5b5b): undefined reference to `Restart()'
csocket.cpp:(.text+0x5bb0): undefined reference to `ourMainInputBuffer'
csocket.cpp:(.text+0x5bd6): undefined reference to `ourMainOutputBuffer'
/tmp/ccwtMWsK.o: In function `ClearWhereInSentence()':
dictionarySystem.cpp:(.text+0x35d): undefined reference to `documentMode'
/tmp/ccwtMWsK.o: In function `AllocateWhereInSentence(WORDENTRY*)':
dictionarySystem.cpp:(.text+0x5ce): undefined reference to `documentMode'
/tmp/ccwtMWsK.o: In function `UseDictionaryFile(char*)':
dictionarySystem.cpp:(.text+0xefc): undefined reference to `language'
dictionarySystem.cpp:(.text+0xf1f): undefined reference to `language'
dictionarySystem.cpp:(.text+0xf3a): undefined reference to `language'
/tmp/ccwtMWsK.o: In function `ReadForeignPosTags(char*)':
dictionarySystem.cpp:(.text+0x10a0): undefined reference to `readBuffer'
dictionarySystem.cpp:(.text+0x10d9): undefined reference to `readBuffer'
/tmp/ccwtMWsK.o: In function `BuildDictionary(char*)':
dictionarySystem.cpp:(.text+0x1402): undefined reference to `language'
dictionarySystem.cpp:(.text+0x157f): undefined reference to `language'
dictionarySystem.cpp:(.text+0x165c): undefined reference to `users'
dictionarySystem.cpp:(.text+0x16ba): undefined reference to `CreateSystem()'
/tmp/ccwtMWsK.o: In function `StoreWord(char*, unsigned long long)':
dictionarySystem.cpp:(.text+0x2915): undefined reference to `server'
/tmp/ccwtMWsK.o: In function `ShowStats(bool)':
dictionarySystem.cpp:(.text+0x31bb): undefined reference to `volleyStartTime'
dictionarySystem.cpp:(.text+0x31c8): undefined reference to `inputSentenceCount'
dictionarySystem.cpp:(.text+0x31d2): undefined reference to `inputSentenceCount'
dictionarySystem.cpp:(.text+0x322b): undefined reference to `tokenCount'
dictionarySystem.cpp:(.text+0x3266): undefined reference to `tokenCount'
dictionarySystem.cpp:(.text+0x326c): undefined reference to `inputSentenceCount'

Answer 1

I could compile my program with this command:

g++ -std=c++11 main.cpp constructCode.cpp duktape/duktape.cpp evserver.cpp csocket.cpp cs_ev.c dictionarySystem.cpp englishTagger.cpp factSystem.cpp json.cpp functionExecute.cpp english.cpp infer.cpp javascript.cpp jsmn.cpp markSystem.cpp mysql.cpp mongodb.cpp os.cpp outputSystem.cpp patternSystem.cpp postgres.cpp privatesrc.cpp scriptCompile.cpp spellcheck.cpp secure.cpp systemVariables.cpp tagger.cpp testing.cpp textUtilities.cpp tokenSystem.cpp topicSystem.cpp userCache.cpp userSystem.cpp variableSystem.cpp mainSystem.cpp -o myapp -L/usr/lib64 -lrt -lcurl -pthread -Ievserver -DDISCARDSERVER=1 -DDISCARDPOSTGRES=1 -DDISCARDMONGO=1 -DDISCARDMYSQL=1 -DEVSERVER=1 -DEVSERVER_FORK=1

I found the options from my makefile and added them at the end of my command as you can see (after -o myapp)

Answer 2

You can't compile with just the header (.h) files. The header files provide the signatures, but the implementations are in object (.o) files, and need to be linked by the compiler.

Answer 3

With g++ -0 test test.cpp, you tell the compiler to compile and link the program, but you miss to tell the compiler where to find the necessary libraries for linking.

If you write g++ -o test.o -c test.cpp, then the compiler will just compile, not link, and you should get a valid test.o object file.

Then, you can link everything together. For that, load down a binary from your GIT repository; I suppose it's the LinuxChatScript64 file. Place the file, let's say, in the same directory where your .cpp-file resides.

Then, link with:

g++ -o myprogram test.o LinuxChatScript64

Hope it works. Good luck!