Im running linux x86_64 I copeid bzfsAPI.h from bzflag-2.0.12/include to the directory of flagOnSpawn/ and then did 'gcc flagOnSpawn.cpp' and got this error :
/usr/lib/gcc/x86_64-pc-linux-gnu/4.1.2/../../../../lib64/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
/tmp/cc3N5rVd.o: In function `FlagOnSpawnHandler::process(bz_EventData*)':
flagOnSpawn.cpp:(.text+0x9f): undefined reference to `bz_getPlayerByIndex(int)'
flagOnSpawn.cpp:(.text+0xce): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::c_str() const'
flagOnSpawn.cpp:(.text+0xf2): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::c_str() const'
flagOnSpawn.cpp:(.text+0x102): undefined reference to `bz_givePlayerFlag(int, char const*, bool)'
flagOnSpawn.cpp:(.text+0x147): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text+0x150): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::c_str() const'
flagOnSpawn.cpp:(.text+0x167): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text+0x185): undefined reference to `bz_sendTextMessage(int, int, char const*)'
flagOnSpawn.cpp:(.text+0x18e): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text+0x1a1): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text+0x1bd): undefined reference to `bz_debugMessage(int, char const*)'
flagOnSpawn.cpp:(.text+0x1c6): undefined reference to `bz_freePlayerRecord(bz_PlayerRecord*)'
/tmp/cc3N5rVd.o: In function `bz_Unload':
flagOnSpawn.cpp:(.text+0x1e1): undefined reference to `bz_removeEvent(bz_eEventType, bz_EventHandler*)'
flagOnSpawn.cpp:(.text+0x1f0): undefined reference to `bz_debugMessage(int, char const*)'
/tmp/cc3N5rVd.o: In function `bz_Load':
flagOnSpawn.cpp:(.text+0x217): undefined reference to `bz_debugMessage(int, char const*)'
flagOnSpawn.cpp:(.text+0x226): undefined reference to `bz_registerEvent(bz_eEventType, bz_EventHandler*)'
flagOnSpawn.cpp:(.text+0x22f): undefined reference to `std::allocator<char>::allocator()'
flagOnSpawn.cpp:(.text+0x240): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&)'
flagOnSpawn.cpp:(.text+0x249): undefined reference to `std::allocator<char>::~allocator()'
flagOnSpawn.cpp:(.text+0x262): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned long)'
flagOnSpawn.cpp:(.text+0x27f): undefined reference to `std::allocator<char>::~allocator()'
flagOnSpawn.cpp:(.text+0x300): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned long)'
flagOnSpawn.cpp:(.text+0x339): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned long)'
flagOnSpawn.cpp:(.text+0x34f): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned long)'
flagOnSpawn.cpp:(.text+0x3ab): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned long)'
flagOnSpawn.cpp:(.text+0x3c9): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::c_str() const'
flagOnSpawn.cpp:(.text+0x53b): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)'
flagOnSpawn.cpp:(.text+0x5d1): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)'
flagOnSpawn.cpp:(.text+0x65f): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)'
flagOnSpawn.cpp:(.text+0x6a3): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)'
flagOnSpawn.cpp:(.text+0x6e7): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)'
/tmp/cc3N5rVd.o:flagOnSpawn.cpp:(.text+0x72b): more undefined references to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)' follow
/tmp/cc3N5rVd.o: In function `bz_Load':
flagOnSpawn.cpp:(.text+0x1278): undefined reference to `bz_debugMessage(int, char const*)'
flagOnSpawn.cpp:(.text+0x129e): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)'
flagOnSpawn.cpp:(.text+0x12bc): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*)'
flagOnSpawn.cpp:(.text+0x12d3): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text+0x12f2): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
/tmp/cc3N5rVd.o: In function `bz_EventHandler::~bz_EventHandler()':
flagOnSpawn.cpp:(.text._ZN15bz_EventHandlerD2Ev[bz_EventHandler::~bz_EventHandler()]+0x26): undefined reference to `operator delete(void*)'
/tmp/cc3N5rVd.o: In function `FlagOnSpawnHandler::~FlagOnSpawnHandler()':
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD0Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0x4e): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD0Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0xc3): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD0Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0x10b): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD0Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0x158): undefined reference to `operator delete(void*)'
/tmp/cc3N5rVd.o: In function `FlagOnSpawnHandler::FlagOnSpawnHandler()':
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerC1Ev[FlagOnSpawnHandler::FlagOnSpawnHandler()]+0x45): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerC1Ev[FlagOnSpawnHandler::FlagOnSpawnHandler()]+0xb6): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerC1Ev[FlagOnSpawnHandler::FlagOnSpawnHandler()]+0xce): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerC1Ev[FlagOnSpawnHandler::FlagOnSpawnHandler()]+0x126): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerC1Ev[FlagOnSpawnHandler::FlagOnSpawnHandler()]+0x171): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
/tmp/cc3N5rVd.o: In function `bz_EventHandler::~bz_EventHandler()':
flagOnSpawn.cpp:(.text._ZN15bz_EventHandlerD0Ev[bz_EventHandler::~bz_EventHandler()]+0x26): undefined reference to `operator delete(void*)'
/tmp/cc3N5rVd.o: In function `bz_EventHandler::~bz_EventHandler()':
flagOnSpawn.cpp:(.text._ZN15bz_EventHandlerD1Ev[bz_EventHandler::~bz_EventHandler()]+0x26): undefined reference to `operator delete(void*)'
/tmp/cc3N5rVd.o: In function `FlagOnSpawnHandler::~FlagOnSpawnHandler()':
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD1Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0x4e): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD1Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0xc3): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD1Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0x10b): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
flagOnSpawn.cpp:(.text._ZN18FlagOnSpawnHandlerD1Ev[FlagOnSpawnHandler::~FlagOnSpawnHandler()]+0x158): undefined reference to `operator delete(void*)'
/tmp/cc3N5rVd.o: In function `std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_EPKS3_RKS6_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x27): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string()'
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_EPKS3_RKS6_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x30): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const'
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_EPKS3_RKS6_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x40): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::reserve(unsigned long)'
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_EPKS3_RKS6_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x51): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::append(char const*, unsigned long)'
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_EPKS3_RKS6_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x5e): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::append(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_EPKS3_RKS6_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x71): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
/tmp/cc3N5rVd.o: In function `std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)':
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_ERKS6_PKS3_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)]+0x1e): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_ERKS6_PKS3_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)]+0x2b): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::append(char const*)'
flagOnSpawn.cpp:(.text._ZStplIcSt11char_traitsIcESaIcEESbIT_T0_T1_ERKS6_PKS3_[std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)]+0x3e): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()'
/tmp/cc3N5rVd.o: In function `bool std::operator!=<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)':
flagOnSpawn.cpp:(.text._ZStneIcSt11char_traitsIcESaIcEEbRKSbIT_T0_T1_EPKS3_[bool std::operator!=<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)]+0x19): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::compare(char const*) const'
/tmp/cc3N5rVd.o: In function `bool std::operator==<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)':
flagOnSpawn.cpp:(.text._ZSteqIcSt11char_traitsIcESaIcEEbRKSbIT_T0_T1_EPKS3_[bool std::operator==<char, std::char_traits<char>, std::allocator<char> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*)]+0x19): undefined reference to `std::basic_string<char, std::char_traits<char>, std::allocator<char> >::compare(char const*) const'
/tmp/cc3N5rVd.o:(.rodata._ZTI18FlagOnSpawnHandler[typeinfo for FlagOnSpawnHandler]+0x0): undefined reference to `vtable for __cxxabiv1::__si_class_type_info'
/tmp/cc3N5rVd.o:(.rodata._ZTI15bz_EventHandler[typeinfo for bz_EventHandler]+0x0): undefined reference to `vtable for __cxxabiv1::__class_type_info'
/tmp/cc3N5rVd.o:(.rodata._ZTV15bz_EventHandler[vtable for bz_EventHandler]+0x20): undefined reference to `__cxa_pure_virtual'
/tmp/cc3N5rVd.o:(.eh_frame+0x13): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status
if that is the wrong way to compile it plz let me know how --MDKSPR
