I am trying to set up a connection to a MySQL database. The code compiles fine, but when linking I always get errors. I've tried both dynamic and static linking but nothing works. Some of the errors:
Severity Code Description Project File Line Suppression State
Error LNK2019 unresolved external symbol "__declspec(dllimport) public: __thiscall mysqlx::abi2::r0::Error::Error(char const *)" (__imp_??0Error#r0#abi2#mysqlx##QAE#PBD#Z) referenced in function "protected: void __thiscall mysqlx::abi2::r0::Value::check_type(enum mysqlx::abi2::r0::Value::Type)const " (?check_type#Value#r0#abi2#mysqlx##IBEXW4Type#1234##Z) DatabaseTest
Severity Code Description Project File Line Suppression State
Error LNK2019 unresolved external symbol "__declspec(dllimport) public: __thiscall mysqlx::abi2::r0::DbDoc::~DbDoc(void)" (__imp_??1DbDoc#r0#abi2#mysqlx##QAE#XZ) referenced in function "public: __thiscall mysqlx::abi2::r0::Value::~Value(void)" (??1Value#r0#abi2#mysqlx##QAE#XZ) DatabaseTest
Severity Code Description Project File Line Suppression State
Error LNK2019 unresolved external symbol "__declspec(dllimport) public: __thiscall mysqlx::abi2::r0::DbDoc::DbDoc(void)" (__imp_??0DbDoc#r0#abi2#mysqlx##QAE#XZ) referenced in function "public: __thiscall mysqlx::abi2::r0::Value::Value(void)" (??0Value#r0#abi2#mysqlx##QAE#XZ) DatabaseTest
#include <iostream>
#include "mysqlx/xdevapi.h"
int main()
{
//short test, program doesn't compile, the headers aren't included here because they are more than 1000 lines long. You can get them at the MySQL homepage
return 0;
}
I use the newest version of the connector. You can download the project here if you want to check the settings. Does anybody have an idea?
First, find where is your mysqlx directory is located, using following command:
sudo find / -name mysqlx
In Debian system, it is usually located in /usr/include/mysql-cppconn-8/ .
For compiling, use folllowing command:
g++ -std=c++11 -I /usr/include/mysql-cppconn-8/ -lmysqlcppconn8 filename.cpp
Related
i want to use taglib in my QT project on windows, so i build taglib and zlib from source like below:
cmake CMakeLists.txt
cmake --build --config release
cmake command uses visual studio compiler, i build zlib and taglib from source with above command with no error, i added their include and lib path to QT project .pro file like below:
INCLUDEPATH+=F:\project\TAGLIB\taglib\taglib F:\project\TAGLIB\taglib\taglib\toolkit F:\project\TAGLIB\taglib F:\project\zlib-1.2.11\Release F:\project\zlib-1.2.11
LIBS+=-LF:\project\zlib-1.2.11\Release -lzlib
LIBS+= -LF:\project\TAGLIB\taglib\taglib\Release -ltag
LIBS+=-LF:\project\TAGLIB\taglib\taglib\Debug -ltag
LIBS+=-LF:\project\zlib-1.2.11\Debug -lzlibd
and in main.cpp i added:
#include<fileref.h>
#include<tag.h>
#include<QDebug>
and in main function:
TagLib::FileRef f("C:\\Users\\sub\\Downloads\\Mohsen Chavoshi - Sharhe Alef.mp3");
TagLib::String artist = f.tag()->artist();
when i run my application in debug mode,it doesn't run and give me below errors:
main.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl TagLib::String::~String(void)" (__imp_??1String#TagLib##UEAA#XZ) referenced in function main
main.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: char const * __cdecl TagLib::String::toCString(bool)const " (__imp_?toCString#String#TagLib##QEBAPEBD_N#Z) referenced in function main
main.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl TagLib::FileName::FileName(char const *)" (__imp_??0FileName#TagLib##QEAA#PEBD#Z) referenced in function main
main.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl TagLib::FileRef::FileRef(class TagLib::FileName,bool,enum TagLib::AudioProperties::ReadStyle)" (__imp_??0FileRef#TagLib##QEAA#VFileName#1#_NW4ReadStyle#AudioProperties#1##Z) referenced in function main
main.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl TagLib::FileRef::~FileRef(void)" (__imp_??1FileRef#TagLib##UEAA#XZ) referenced in function main
main.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: class TagLib::Tag * __cdecl TagLib::FileRef::tag(void)const " (__imp_?tag#FileRef#TagLib##QEBAPEAVTag#2#XZ) referenced in function main
debug\testTag2.exe:-1: error: LNK1120: 6 unresolved externals
but when i run application in Release mode,the above error are just some Warning and application run with no problem, why this is happening?
thank you.
I'm new and trying to use Quazip under qt 5.5. So I just downloaded project sources from http://quazip.sourceforge.net/ and opened .pro file. When I try to build project I 've got multiple errors:
C1083: Cannot open include file: 'zlib.h': No such file or directory
To avoid building zlib on windows I just installed (from here: http://gnuwin32.sourceforge.net/packages/zlib.htm) complete pack for windows in C:\GnuWin32. Then I added this line in .pro file:
INCLUDEPATH += C:\GnuWin32\include
This generated another error:
Cannot open include file: 'unistd.h': No such file or directory
But changing this line
#if 1 /* HAVE_UNISTD_H -- this line is updated by ./configure */
into this fixed the problem.
#if HAVE_UNISTD_H
Unfortunately now I get 25 unresolved external symbols, some of them:
quaadler32.obj:-1: error: LNK2019: unresolved external symbol adler32 referenced in function "public: virtual unsigned int __cdecl QuaAdler32::calculate(class QByteArray const &)" (?calculate#QuaAdler32##UEAAIAEBVQByteArray###Z)
quacrc32.obj:-1: error: LNK2019: unresolved external symbol crc32 referenced in function "public: virtual unsigned int __cdecl QuaCrc32::calculate(class QByteArray const &)" (?calculate#QuaCrc32##UEAAIAEBVQByteArray###Z)
unzip.obj:-1: error: LNK2001: unresolved external symbol crc32
quagzipfile.obj:-1: error: LNK2019: unresolved external symbol gzopen referenced in function "private: void * __cdecl QuaGzipFilePrivate::open(class QString const &,char const *)" (?open#QuaGzipFilePrivate##AEAAPEAXAEBVQString##PEBD#Z)
quaziodevice.obj:-1: error: LNK2019: unresolved external symbol deflateInit_ referenced in function "public: virtual bool __cdecl QuaZIODevice::open(class QFlags<enum QIODevice::OpenModeFlag>)" (?open#QuaZIODevice##UEAA_NV?$QFlags#W4OpenModeFlag#QIODevice#####Z)
quaziodevice.obj:-1: error: LNK2019: unresolved external symbol inflate referenced in function "protected: virtual __int64 __cdecl QuaZIODevice::readData(char *,__int64)" (?readData#QuaZIODevice##MEAA_JPEAD_J#Z)
I tries adding this line:
LIBS += -LC:\GnuWin32\lib
But that didn't solve the problem. WHat is the easiest way to use Quazip under Qt?
Download quazip source from quzip site
Open by Qt Creator quazip.pri
Replace all strings #include "zlib.h" or "#include < zlib.h>"
to
#include <QtZlib/zlib.h>
Build project and run unit tests.
I'm trying to code a program that can edit mp3 tag.
And now,I have a problem.
That is,when I compile,there is always errors.
and the error is Linker error.
Here is error descriptions:
error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall ID3_Tag::ID3_Tag(char const *)" (__imp_??0ID3_Tag##QAE#PBD#Z) referenced in function _wmain
error LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __thiscall ID3_Tag::~ID3_Tag(void)" (__imp_??1ID3_Tag##UAE#XZ) referenced in function _wmain
Does anyone know how or what to do??
You probably didn't link against the appropriate libraries, where the symbols the linker is complaining about are exported.
Here's how to link against the libs which are probably found in this archive (version number subject to change).
I am trying to use the amalgamated version of jsoncpp(the latest version), but it is producing unresolved external symbol link errors. The code I am using is
#include <json/json.h>
int main(){
Json::Value root;
return 0;
}
and it is giving me the error
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall Json::Value::~Value(void)" (??1Value#Json##QAE#XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall Json::Value::Value(enum Json::ValueType)" (??0Value#Json##QAE#W4ValueType#1##Z) referenced in function _main
Probably you didn't include the JSONCPPs *.cpp file into your project (they have to be compiled and linked). If the library gets compiled to a static library, you have to tell the linker what to link.
I got this when trying to link x86 version of JsonCpp in my x64 build. I did not notice that Vcpkg behaves as if VCPKG_DEFAULT_TRIPLET=x86-windows was defined, unless it's told otherwise.
I saw the following entry in the build log when that was happening
C:\Tools\vcpkg\installed\x86-windows\debug\lib\jsoncpp.lib : warning LNK4272: library machine type 'x86' conflicts with target machine type 'x64' [C:\projects\qpid-proton\BLD\cpp\qpid-proton-cpp.vcxproj]
I am creating an torrent application using libtorrent in VS 2008. I tried the example given in the link http://www.rasterbar.com/products/libtorrent/examples.html
BUt it is showing me these error....how to solve them?
Linking...
main.obj : error LNK2019: unresolved external symbol "public: __thiscall libtorrent::torrent_info::~torrent_info(void)" (??1torrent_info#libtorrent##QAE#XZ) referenced in function _main
main.obj : error LNK2019: unresolved external symbol "public: __thiscall libtorrent::torrent_info::torrent_info(struct libtorrent::lazy_entry const &)" (??0torrent_info#libtorrent##QAE#ABUlazy_entry#1##Z) referenced in function _main
main.obj : error LNK2019: unresolved external symbol "class std::basic_ostream > & __cdecl libtorrent::operator<<(class std::basic_ostream > &,struct libtorrent::lazy_entry const &)" (??6libtorrent##YAAAV?$basic_ostream#DU?$char_traits#D#std###std##AAV12#ABUlazy_entry#0##Z) referenced in function _main
main.obj : error LNK2019: unresolved external symbol "int __cdecl libtorrent::lazy_bdecode(char const *,char const *,struct libtorrent::lazy_entry &,int)" (?lazy_bdecode#libtorrent##YAHPBD0AAUlazy_entry#1#H#Z) referenced in function _main
main.obj : error LNK2019: unresolved external symbol "public: void __thiscall libtorrent::lazy_entry::clear(void)" (?clear#lazy_entry#libtorrent##QAEXXZ) referenced in function "public: __thiscall libtorrent::lazy_entry::~lazy_entry(void)" (??1lazy_entry#libtorrent##QAE#XZ)
main.obj : error LNK2019: unresolved external symbol "void __cdecl libtorrent::to_hex(char const *,int,char *)" (?to_hex#libtorrent##YAXPBDHPAD#Z) referenced in function "class std::basic_ostream > & __cdecl libtorrent::operator<<(class std::basic_ostream > &,class libtorrent::big_number const &)" (??6libtorrent##YAAAV?$basic_ostream#DU?$char_traits#D#std###std##AAV12#ABVbig_number#0##Z)
main.obj : error LNK2019: unresolved external symbol "public: struct libtorrent::peer_request __thiscall libtorrent::file_storage::map_file(int,__int64,int)const " (?map_file#file_storage#libtorrent##QBE?AUpeer_request#2#H_JH#Z) referenced in function "public: struct libtorrent::peer_request __thiscall libtorrent::torrent_info::map_file(int,__int64,int)const " (?map_file#torrent_info#libtorrent##QBE?AUpeer_request#2#H_JH#Z)
C:\Users\photoshop3\Documents\Visual Studio 2008\Projects\Lib2\Debug\Lib2.exe : fatal error LNK1120: 7 unresolved externals
The .lib is not included in your project. Make sure you are linking it in;
Configuration Properties -> Linker -> Input -> Additional Dependencies
Another altnerative is to simply copy the .lib to your project folder but don't, it's bound to create problems later on.
Sometimes the .lib is not shipped with the library, so you need to compile it yourself.
The README will tell you this. If this is the case, they usually ship with a .sln file you can open and the just compile it into a .lib file which you then reference in your main application, as I wrote above
Have you added the path of header files in the "Configuration Properties" --> "C/C++“ --> "General" --> "Additional Include Directories"?
The link gives you only the sources (including headerfiles) of libtorrent. You should compile this sources to get a .lib file. Add this .lib file to your client:
Configuration Properties/Linker/Input -> Additional Dependencies: libtorrent-rasterbar.lib
The best starting point for compiling should be the README file.
public: isn't the unresolved symbol. It's just there because the linker it trying to tell you that (most) of the unresolved symbols are public member functions.
It looks like you've included the header for "libtorrent", but not linked to the "libtorrent" library.
You have probably not linked with the torrent library or specified the wrong path to it so that the linker cannot find it.
If the input libraries are of 32bit and your are using them in building a 64bit it might be one of the reasons
For me, I had it included in my project, but it turned out that it was a plugin that was designed to not create an instance of in my unit test.