log4cpp gives `unresolved external` errors - c++

Question

I'm trying to make work the library and run the tests provided with the latest version of log4cpp on Borland Codegear 2007, in which it's included a bpr project for Borland C++ Builder 5, which is meant to be able to build and run the different tests. The problem is that I'm trying to open this project with the 2007 version, which has to carry out a project conversion. I was getting weird 'unresolved external' errors. Then I've tried to build the project myself without converting anything, but got stuck in the same point.
I'm trying to run the following test :
#include <stdio.h>
#include "log4cpp/Portability.hh"
#ifdef LOG4CPP_HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <iostream>
#include "log4cpp/Category.hh"
#include "log4cpp/Appender.hh"
#include "log4cpp/FileAppender.hh"
#include "log4cpp/OstreamAppender.hh"
#ifdef LOG4CPP_HAVE_SYSLOG
#include "log4cpp/SyslogAppender.hh"
#endif
#include "log4cpp/Layout.hh"
#include "log4cpp/BasicLayout.hh"
#include "log4cpp/Priority.hh"
#include "log4cpp/NDC.hh"
int main(int argc, char** argv) {
log4cpp::Appender* appender;
#ifdef LOG4CPP_HAVE_SYSLOG
log4cpp::SyslogAppender* syslogAppender;
syslogAppender = new log4cpp::SyslogAppender("syslog", "log4cpp");
#else
log4cpp::Appender* syslogAppender;
syslogAppender = new log4cpp::OstreamAppender("syslogdummy", &std::cout);
#endif
if (argc < 2) {
appender = new log4cpp::OstreamAppender("default", &std::cout);
} else {
appender = new log4cpp::FileAppender("default", argv[1]);
}
syslogAppender->setLayout(new log4cpp::BasicLayout());
appender->setLayout(new log4cpp::BasicLayout());
log4cpp::Category& root = log4cpp::Category::getRoot();
root.addAppender(syslogAppender);
root.setPriority(log4cpp::Priority::ERROR);
log4cpp::Category& sub1 = log4cpp::Category::getInstance(std::string("sub1"));
sub1.addAppender(appender);
log4cpp::Category& sub2 = log4cpp::Category::getInstance(std::string("sub1.sub2"));
log4cpp::NDC::push(std::string("ndc1"));
std::cout << " root prio = " << root.getPriority() << std::endl;
std::cout << " sub1 prio = " << sub1.getPriority() << std::endl;
std::cout << " sub2 prio = " << sub2.getPriority() << std::endl;
root.error("root error");
root.warn("root warn");
sub1.error("sub1 error");
sub1.warn("sub1 warn");
sub2.error("sub2 error");
sub2.warn("sub2 warn");
sub1.setPriority(log4cpp::Priority::INFO);
std::cout << " root prio = " << root.getPriority() << std::endl;
std::cout << " sub1 prio = " << sub1.getPriority() << std::endl;
std::cout << " sub2 prio = " << sub2.getPriority() << std::endl;
std::cout << "priority info" << std::endl;
root.error("root error");
root.warn("root warn");
sub1.error("sub1 error");
sub1.warn("sub1 warn");
sub2.error("sub2 error");
sub2.warn("sub2 warn");
sub2.warnStream() << "streamed warn";
sub2 << log4cpp::Priority::WARN << "warn2" << " warn3"
<< log4cpp::eol << " warn4";
{
for(int i = 0; i < 10000; i++) {
char ndc2[20];
sprintf(ndc2, "i=%d", i);
log4cpp::NDC::push(ndc2);
sub1.info("%s%d", "i = ", i);
if ((i % 10) == 0) {
sub1.log(log4cpp::Priority::NOTICE, "reopen log");
if (log4cpp::Appender::reopenAll()) {
sub1.info("log reopened");
} else {
sub1.warn("could not reopen log");
}
}
#ifndef WIN32
sleep(1);
#endif
log4cpp::NDC::pop();
}
}
return 0;
}
The errors are all about 'unresolved external', such as:
[ILINK32 Error] Error: Unresolved external 'log4cpp::Category::warn(const char *, ...)' referenced from C:\DOCUMENTS AND SETTINGS\MLERMA\MIS DOCUMENTOS\RAD STUDIO\PROJECTS\DEBUG\TESTMAIN.OBJ
I'm getting this kind of error for every single call to a log4cpp function, all referring to TESTMAIN.OBJ .
Any ideas on this? is there anyone out there who has worked with log4cpp on Borland ?

Answer 1

Are you linking in the log4cpp library (.LIB)? I'm not familiar with BCB5 or Codegear but check your link libraries in your project settings and make sure the log4cpp library is included.
If it is, then you might have a problem with where the compiler is looking for libraries. Usually an IDE will have a project level or global setting that says where there compiler will look for .lib files. Check that setting and make sure one of those directories includes your log4cpp .lib file.
Mike

Answer 2

Try adding #pragma comment(lib,"ws2_32.lib") do your header file.