G++: fatal error: no input files - opencv

Question

Hi Im trying to display the lena.jpg which is the first demostration for Instant OpenCV Starter Book.
I can build and play 'hello world' easy enough.
The problem code
// opencv header files
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/core/core.hpp"
// namespaces declaration
using namespace cv;
using namespace std;
// create a variable to store the image
Mat image;
int main( int argc, char** argv )
{
// open the image and store it in the 'image' variable
// Replace the path with where you have downloaded the image
// image=imread("<path to image">/lena.jpg");
image=imread("/home/nigel/Documents/ffmpeg/tests/lena.jpg");
// create a window to display the image
namedWindow( "Display window", CV_WINDOW_AUTOSIZE );
// display the image in the window created
imshow( "Display window", image );
// wait for a keystroke
waitKey(0);
return 0;
}
The error
g++ -Wall -fexceptions 'pkg-config --cflags opencv' -g "pkg-config --cflags
opencv' -c/home/nigel/Drone/Test2/main.cpp -o obj/Debug/Drone/Test2/main.o
g++:fatal error:no input files
compilation terminated
process terminated with status 1 (0 minutes, 0 seconds)
I have tried different paths for the lena.jpg, I changed the lena.jpg from lena.pnm not sure if I have the path right maybe ?
New to using OpenCv would appreciate some help

Answer 1

This error occurs when no source code file is passed in to g++. This leads me to believe there is an error in your command line arguments.
Some spots to look at:
It looks like there may be a stray quote before the second pkg-config in the line
'pkg-config --cflags opencv' -g "pkg-config --cflags opencv'
It also looks like you are missing a space between the -c and the /home/.../main.cpp