g++ -c main.cc
main.cc:8: warning: this decimal constant is unsigned only in ISO C90
main.cc:9: warning: this decimal constant is unsigned only in ISO C90
main.cc:9: warning: this decimal constant is unsigned only in ISO C90
main.cc:10: warning: this decimal constant is unsigned only in ISO C90
g++ -c iplookup.cc
g++ -c iproute.cc
g++ main.o iplookup.o iproute.o -o main
iplookup.o: In function `iplookup::show_gateway(unsigned int)':
iplookup.cc:(.text+0x1c4): undefined reference to `iproute::getMask()'
iplookup.cc:(.text+0x1dc): undefined reference to `iproute::getAddr()'
iplookup.cc:(.text+0x206): undefined reference to `iproute::getMask()'
iplookup.cc:(.text+0x290): undefined reference to `iproute::getGw()'
iplookup.o: In function `iplookup::update_entry(iproute, iproute)':
iplookup.cc:(.text+0x316): undefined reference to `iproute::getAddr()'
iplookup.cc:(.text+0x32f): undefined reference to `iproute::setAddr(unsigned int)'
iplookup.cc:(.text+0x33a): undefined reference to `iproute::getMask()'
iplookup.cc:(.text+0x353): undefined reference to `iproute::setMask(unsigned int)'
iplookup.cc:(.text+0x35e): undefined reference to `iproute::getGw()'
iplookup.cc:(.text+0x377): undefined reference to `iproute::setGw(unsigned int)'
iplookup.o: In function `iplookup::entries_match(iproute, iproute)':
iplookup.cc:(.text+0x3e6): undefined reference to `iproute::getAddr()'
iplookup.cc:(.text+0x3f3): undefined reference to `iproute::getAddr()'
iplookup.cc:(.text+0x402): undefined reference to `iproute::getMask()'
iplookup.cc:(.text+0x40f): undefined reference to `iproute::getMask()'
iplookup.cc:(.text+0x41e): undefined reference to `iproute::getGw()'
iplookup.cc:(.text+0x42b): undefined reference to `iproute::getGw()'
collect2: ld returned 1 exit status
make: *** [main] Error 1