Facing issues with CPP Quick Start example

[shriyog]

Facing issues with the CPP example mentioned in https://github.com/yahoojapan/NGT/wiki/Cpp-Quick-Start

I've built & installed NGT as mentioned in https://github.com/yahoojapan/NGT#on-linux but getting following error while running the construct.cpp code given in the quick start.

g++ -std=c++11 -o construct -lngt construct.cpp 

/tmp/ccRBjxzo.o: In function `NGT::Index::Index(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)':
construct.cpp:(.text._ZN3NGT5IndexC2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEb[_ZN3NGT5IndexC5ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEb]+0xc4): undefined reference to `NGT::Index::open(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
/tmp/ccRBjxzo.o: In function `NGT::Index::createGraphAndTree(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, NGT::Property&, bool)':
construct.cpp:(.text._ZN3NGT5Index18createGraphAndTreeERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERNS_8PropertyEb[_ZN3NGT5Index18createGraphAndTreeERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERNS_8PropertyEb]+0x65): undefined reference to `NGT::Index::createGraphAndTree(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, NGT::Property&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned long, bool)'
collect2: error: ld returned 1 exit status

[masajiro]

It seems that libngt is not installed properly. What is your OS? Can you run the command line tool "ngt"?

[shriyog]

Hey @masajiro — Thanks for replying! I've built this on Ubuntu 18.04.3 & can see the libraries installed

> ldconfig -p | grep libngt*
libngt.so.1 (libc6,x86-64) => /usr/local/lib/libngt.so.1
libngt.so (libc6,x86-64) => /usr/local/lib/libngt.so
libnghttp2.so.14 (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libnghttp2.so.14

Also, I can't get ngt cli working

> ngt --help
ngt: symbol lookup error: ngt: undefined symbol: _ZN3NGT7Command6searchERNS_5IndexERNS0_15SearchParameterERSiRSo

I had tried setting this up locally on MacOS - the ngt cli works but can't get the cpp examples running.

[masajiro]

I cannot reproduce your situation. Could you run the commands below?

$ ldd `which ngt`|grep ngt
        libngt.so.1 => /usr/local/lib/libngt.so.1 (0x00007fc387bad000)

$ c++filt _ZN3NGT7Command6searchERNS_5IndexERNS0_15SearchParameterERSiRSo
NGT::Command::search(NGT::Index&, NGT::Command::SearchParameter&, std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&)

$ nm /usr/local/lib/libngt.so.1.* | c++filt | grep NGT::Command::search
0000000000061bb0 T NGT::Command::search(NGT::Args&)
000000000005e090 T NGT::Command::search(NGT::Index&, NGT::Command::SearchParameters&, std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&)

[shriyog]

@masajiro Here's my output

$ ldd `which ngt`|grep ngt
libngt.so.1 => /usr/local/lib/libngt.so.1 (0x00007fd46fb16000)

$ c++filt _ZN3NGT7Command6searchERNS_5IndexERNS0_15SearchParameterERSiRSo
NGT::Command::search(NGT::Index&, NGT::Command::SearchParameter&, std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&)

$ nm /usr/local/lib/libngt.so.1.* | c++filt | grep NGT::Command::search
000000000005a3e0 T NGT::Command::search(NGT::Args&)
00000000000566e0 T NGT::Command::search(NGT::Index&, NGT::Command::SearchParameters&, std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&)
0000000000040fd0 T NGT::Command::search(NGT::Args&)
000000000003e620 T NGT::Command::search(NGT::Index&, NGT::Command::SearchParameter&, std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&)

[masajiro]

I think that there are 2 versions of libngt from your output. "ngt" of v1.12 refers libngt of v1.13. You may want to build and install the latest NGT (v1.13.8). Then, please make sure that you use the reinstalled commands, libraries and headers .

[shriyog]

@masajiro I've built & installed the latest release you mentioned (v1.13.8) on a new Linux machine. Can see the commands are showing same results as you mentioned.

$ ldd `which ngt`|grep ngt
libngt.so.1 => /usr/local/lib/libngt.so.1 (0x00007f591b4fc000)

$ c++filt _ZN3NGT7Command6searchERNS_5IndexERNS0_15SearchParameterERSiRSo
NGT::Command::search(NGT::Index&, NGT::Command::SearchParameter&, std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&)

$ nm /usr/local/lib/libngt.so.1.* | c++filt | grep NGT::Command::search
000000000005c8b0 T NGT::Command::search(NGT::Args&)
0000000000058b40 T NGT::Command::search(NGT::Index&, NGT::Command::SearchParameters&, std::basic_istream<char, std::char_traits<char> >&, std::basic_ostream<char, std::char_traits<char> >&)

I was able to get the NGT CLI working this time but the CPP sample code is giving the same error again.

$ g++ -std=c++11 -o construct -lngt construct.cpp 
/tmp/cc4CgJRQ.o: In function `NGT::Index::Index(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)':
construct.cpp:(.text._ZN3NGT5IndexC2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEb[_ZN3NGT5IndexC5ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEb]+0xc4): undefined reference to `NGT::Index::open(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
/tmp/cc4CgJRQ.o: In function `NGT::Index::createGraphAndTree(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, NGT::Property&, bool)':
construct.cpp:(.text._ZN3NGT5Index18createGraphAndTreeERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERNS_8PropertyEb[_ZN3NGT5Index18createGraphAndTreeERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERNS_8PropertyEb]+0x65): undefined reference to `NGT::Index::createGraphAndTree(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, NGT::Property&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned long, bool)'

I think the error shows a difference in NGT::Index::createGraphAndTree arguments - an extra string & unsigned long. Is the sample code mentioned in Wiki or anything under samples folder working for you?

[masajiro]

How about this.

g++ -std=c++11 -o construct construct.cpp -lngt

[shriyog]

@masajiro Yes, this worked! Thank you for all your help.