提升线程中的"too few arguments to function"

Question

我正在尝试开发一个立体视觉系统。每当我尝试构建代码时，我都会收到以下消息：

   ***** Build of configuration Debug for project RicoCameraCpp ****
    make all 
    Building file: ../main.cpp
    Invoking: Cross G++ Compiler
    g++ -I/home/ux/Downloads -I/usr/local/boost_1_52_0/boost -I/usr/local/boost_1_52_0 -    I/home/ux/Downloads/opencv2 -include/home/ux/Downloads/opencv2/opencv_modules.hpp -include/usr/local/boost_1_52_0/boost/thread.hpp -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"main.d" -MT"main.d" -o "main.o" "../main.cpp"
In file included from /usr/local/boost_1_52_0/boost/thread/thread.hpp:22:0,
                 from /usr/local/boost_1_52_0/boost/thread.hpp:13,
                 from <command-line>:0:
/usr/local/boost_1_52_0/boost/thread/detail/thread.hpp: In member function ‘void boost::detail::thread_data<F>::run() [with F = int (*)(int, char**)]’:
../main.cpp:81:1:   instantiated from here
    /usr/local/boost_1_52_0/boost/thread/detail/thread.hpp:78:17: error: too few arguments to function
    /usr/local/boost_1_52_0/boost/system/error_code.hpp: At global scope:
    /usr/local/boost_1_52_0/boost/system/error_code.hpp:214:36: warning: ‘boost::system::posix_category’ defined but not used [-Wunused-variable]
    /usr/local/boost_1_52_0/boost/system/error_code.hpp:215:36: warning:     ‘boost::system::errno_ecat’ defined but not used [-Wunused-variable]
    /usr/local/boost_1_52_0/boost/system/error_code.hpp:216:36: warning:     ‘boost::system::native_ecat’ defined but not used [-Wunused-variable]
    make: *** [main.o] Error 1
    **** Build Finished *****

这是我的代码：

#include "cstdlib"
#include "cmath"
#include "opencv/cv.h"
#include "opencv/highgui.h"
#include "boost/thread.hpp"
#include <iostream>
using namespace std;
using namespace boost;
using namespace cv;
int firstCam( int argc, char** argv )
{
    //initilize first camera
    CvCapture* captureRightCam = cvCaptureFromCAM(0);
    //check if first camera is available
    if(!captureRightCam)
        {
        cout << "No first camera to capturen";
            return(-1);
        }
    //create right window
    cvNamedWindow( "Right Cam", CV_WINDOW_AUTOSIZE );
    //display frames for every cvWaitKey duration
    while ( 1 )
        {
            //get frames
        IplImage* rightFrame = cvQueryFrame( captureRightCam );
        //check if captured
        if ( !rightFrame )
        {
            fprintf( stderr, "ERROR: frame is null...n" );
            getchar();
            break;
        }
        //show frames inside the windows
        cvShowImage( "Right Cam", rightFrame );
        cvWaitKey(150);
    }
//release and destroy windows
cvReleaseCapture( &captureRightCam );
cvDestroyWindow( "Right Cam" );
return 0;
}
int secondCam( int argc, char** argv )
{
CvCapture* captureLeftCam = cvCaptureFromCAM(1);
if(!captureLeftCam)
    {
        cout << "No second camera to capturen";
        return(-1);
    }
cvNamedWindow( "Left Cam", CV_WINDOW_AUTOSIZE );
while ( 1 )
    {
        IplImage* leftFrame = cvQueryFrame( captureLeftCam );
        if ( !leftFrame )
        {
            fprintf( stderr, "ERROR: frame is null...n" );
            getchar();
            break;
        }
        cvShowImage( "Left Cam", leftFrame );
        cvWaitKey(150);
    }
cvReleaseCapture( &captureLeftCam );
cvDestroyWindow( "Left Cam" );
return 0;
}
int main()
{
boost::thread t1(firstCam);
boost::thread t2(secondCam);
return 0;
}

我做错了什么？

Answer 1

我认为错误消息是非常描述性的，实际上：

您正试图从函数firstCam中生成一个线程。该函数接受两个参数，但当您创建线程时，不会给它任何参数。因此，它无法确定要传递给函数的参数，因此抱怨"参数太少"。

在这种情况下，您似乎从某个地方复制了函数签名，而没有考虑它。您根本不会使用argc和argv。

（附带说明：

using namespace std;
using namespace boost;
using namespace cv;

是个坏主意，迟早会给你带来麻烦。详见GotW 53。）