I want to use boost filesystem functions and I searched my build log and find these lines:
1> Searching C:\local\boost_1_55_0\stage\lib\libboost_filesystem-vc90-mt-1_55.lib:
1> Searching C:\local\boost_1_55_0\stage\lib\libboost_system-vc90-mt-1_55.lib:
1> Searching C:\local\boost_1_55_0\stage\lib\boost_system-vc90-1_55.lib:
so it did find the libs.
what I med are:
proc1.obj : error LNK2001: unresolved external symbol "unsigned __int64 __cdecl boost::filesystem::detail::file_size(class boost::filesystem::path const &,class boost::system::error_code *)" (?file_size#detail#filesystem#boost##YA_KAEBVpath#23#PEAVerror_code#system#3##Z)
how to solve this?
my test code:
#include <stdlib.h>
#include <string>
#include <iostream>
#include <boost/filesystem.hpp>
#include <boost/foreach.hpp>
using namespace std;
namespace fs = boost::filesystem;
int main()
{
string filepath( "H:\\DataSets\\xxx" );
int a = fs::file_size(filepath.c_str());
}
As you said in your comment, you are only linking with boost::filesystem. boost::filesystem depends on boost::system so you must also link to boost::system
Related
I am relatively new to C++, but have come from Python and C.
I am using an SDK for a lidar sensor. I have 5 main files that are involved; SDK.h, SDK.cpp, setup.h, setup.cpp and main.cpp.
A class is defined within the SDK.
rplidar.h
class RPlidarDriver{
public:
static RPlidarDriver * CreateDriver(_u32 drivertype = DRIVER_TYPE_SERIALPORT);
// more code
}
main.cpp
#include <iostream>
#include "rplidar.h"
#include "setup.h"
using namespace std;
using namespace rp::standalone::rplidar;
int main()
{
//code
RPlidarDriver* lidar = RPlidarDriver::CreateDriver(DRIVER_TYPE_SERIALPORT);
start_reading(lidar, scanMode);
//code
}
setup.cpp
#include "setup.h"
#include "rplidar.h"
using namespace std;
using namespace rp::standalone::rplidar;
void start_reading(RPlidarDriver* driver, const char* scanMode)
{
//start motor
driver->startMotor();
//more code...
}
setup.h
#include "rplidar.h"
using namespace rp::standalone::rplidar;
namespace setup
{
void start_reading(RPlidarDriver* driver, const char* scanMode);
}
However I get this error
main.obj : error LNK2019: unresolved external symbol "void __cdecl setup::start_reading(class rp::standalone::rplidar::RPlidarDriver *,char const *)" (?start_reading#setup##YAXPAVRPlidarDriver#rplidar#standalone#rp##PBD#Z) referenced in function _main
I also get the same error for other functions that I try to use the object as a parameter.
If I put the function in setup.cpp into main.cpp, it compiles easily. I tried to implement & and use the parameter as a reference instead, but not luck.
main.cpp and setup.cpp both need to be compiled and the resulting object files need to be linked together along with the SDK libraries. The error you're getting is telling you you're trying to link the final binary using just main.o and the SDK without setup.o That's why the linker is failing to find the symbol with the implementation of your start_reading function.
I have this project that throws LNK2001 error on using atoi while proper includes added:
#... //other headers
#include <cstdlib>
#include <string>
#include <cstring>
#include <cstdio>
#include <sstream>
#include <iostream>
BOOL main(int argc, char* argv[]){
ShowNumber(atoi(argv[1]));
return TRUE;
}
Error is: LNK2001: Unresolved external symbol _atoi
I do know that LNK error happens while a header confusion occurs. But i don't think that headers are the problem here. Is there anything in the project configuration or header conflict that may cause this to break? Also i get 15 other LNK2001 on using std::stoi.
Visual studio 2017 with 2015 or 2017 toolset.
I am getting the two errors when I try to compile my code. I have defined win32 consile application. I have not even yet started coding. My configurations are the following - Linker - subsytem - Console; Linker - Advanced - Entry Point - Blank.
error LNK2019: unresolved external symbol _main referenced in function
___tmainCRTStartup
Error 2 error LNK1120: 1 unresolved externals
I don't know what happened. Before everything was working fine but from today it does not. Do you have any idea how I can resolve it that?
My code so far is
// ConsoleApplication1.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "tbb/blocked_range.h"
#include "tbb/tbb.h"
#include <stdio.h>
#include <math.h>
#include <iostream>
#include "tbb/parallel_for.h"
#include <sstream>
#include <tbb/task_scheduler_init.h>
using namespace std;
#define PI 3.14159265
using namespace tbb;
// Sequential Execution
class Sequential
{
double * m;
double *n;
public:
Sequential(double n[], double m[]): n(n), m(m){}
void Partition()
{
}
int main(int argc, char** argv)
{
//double a = 5;
//double b = 4;
//Sequential g = Sequential(a,b);
return 0;
}
};
Thanks
The main function must be in the global namespace. C++ is not C#/Java where all functions must be inside classes.
I am just probing some more advanced coding in C++, so imagine my frustration when I can't solve this:
1>Main.obj : error LNK2019: unresolved external symbol "int __cdecl playerAtk(void)" (? playerAtk##YAHXZ) referenced in function _main
1>C:\Users\Hezekiah Detinc\documents\visual studio 2010\Projects\Custom_1\Debug\Custom_1.exe : fatal error LNK1120: 1 unresolved externals
I had tried searching for an answer here, but the solutions I have found were too specific to be of any use for me.
If anyone can answer; What generally causes this problem? What are some solutions to fixing it?
This is my Main.cpp;
//Custom 1
//Include files that may be used. will cut out unused files in release.
#include <iostream>
#include <vector>
#include <string>
#include <cstdlib>
#include <ctime>
#include <algorithm>
#include "EnemyBaseClass.h"
#include "PlayerBaseClass.h"
using namespace std;
int main()
{
Enemy emy;
Player plr;
emy.enemyAtk();
emy.enemyDef();
emy.enemyHp();
plr.playerAtk();
plr.playerDef();
plr.playerHp();
int playerAtk();
cout << playerAtk();
cout << "You're attacked by a Monster!\n";
system(" pause ");
return 0;
}
If I need to post my headers or the other _.cpp files, let me know.
You declare and use playerAtk as a function (with no implementation, thus the undefined reference)
Change
int playerAtk();
...
cout << playerAtk();
to
int playerAtk;
...
cout << playerAtk;
(You probably want to initialize the variable)
The error is simple: You are using a function which you have declared, but you have not written any definition (Implementation). Check your source (.cpp) files.
I have a rather unusual problem. I am trying to do this:
char *content = new char[10000];
std::cin.read(content, 10000);
And I get the following linker error (weird because the code was compiling fine a few weeks ago, and it hasn't been modified):
Error LNK2001: unresolved external symbol "__declspec(dllimport) public: class std::basic_istream<char,struct std::char_traits<char> > & __thiscall std::basic_istream<char,struct std::char_traits<char> >::read(char *,__int64)" (__imp_?read#?$basic_istream#DU?$char_traits#D#std###std##QAEAAV12#PAD_J#Z) main.obj
I verified that I have all the required dependencies linked in the Project Properties, verified that I have /MT set, and the like. The project was compiling fine just a few weeks ago-- the only thing I have done between then and now is update VS2012. Here are my includes.
#include <stdlib.h>
#ifdef _WIN32
#include <process.h>
#else
#include <unistd.h>
extern char ** environ;
#endif
#include "fcgio.h"
#include "fcgi_config.h"
#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>
#include <boost/algorithm/string.hpp>
It appears that after updating Visual Studio 2012, the project (somehow) became non-functional. Copying the exact same code over to a new project has fixed the problem.