I am new to C++ and am trying to build a program which receives data and shall transform and then plot it. For plotting I want to use Sciplot, but when I run the program, the message "The command 'gnuplot' is either spelled wrongly or could not be found." appears. I have installed the newest version of gnuplot (5.4.4), but it seems the program is not able to call it.
Here is the code I use for testing sciplot (example is taken from https://sciplot.github.io/tutorials/):
#include <sciplot/sciplot.hpp>
using namespace sciplot
int main(int argc, char* argv[]
{
Vec x = linspace(0.0, PI, 200);
Plot2D plot;
plot.xlabel("x");
plot.ylabel("y");
plot.xrange(0.0, PI);
plot.yrange(0.0, 1.0);
plot.legend()
.atOutsideBottom()
.displayHorizontal()
.displayExpandWidthBy(2);
plot.drawCurve(x, std::sin(1.0 * x)).label("sin(x)");
plot.drawCurve(x, std::sin(2.0 * x)).label("sin(2x)");
plot.drawCurve(x, std::sin(3.0 * x)).label("sin(3x)");
Figure fig = { {plot} };
Canvas canvas = { {fig} };
canvas.show();
return 0;
}
Do I need to tell Visual Studio the path to gnuplot? Or did I miss something else?
You need to tick the checkmark "Add application directory to your PATH environment variable" on the sixth page of the gnuplot installer. Alternativly add the folder of your gnuplot.exe to your PATH environment variable.
If you use MS Visual Studio for compiling the example, you need to close and re-open MS Visual Studio. MS VS does only "read" environment variables at program start-up.
This sciplot project calls std::system with gnuplot, so your cmd has to recognize the gnuplot command/find the gnuplot exe.
I tested it, and it works like I described.
Related
I have some C++ executables which contain various std::cout outputs.
In Visual Studio 2019 x64 Native Tools Command Prompt, when I run these executables, there is no output displayed on the console.
If I redirect the output to a file, the output is indeed printed to the file.
The following program for example does not output anything to the console:
#include <iostream>
int main (int argc, char** argv) {
std::cout << "Hello world" << std::endl;
}
Is there some setting or variable I need to set in order to see the output in the console itself ?
According to the code you provided, my console program can output normally.
I suggest you could verify that the Visual C++ developer command prompt is set up correctly. In the command prompt window, enter cl and verify that the output looks something like this:
For more details about how to compiling a Native C++ Program on the Command Line, I suggest you could refer to the Doc: Walkthrough: Compiling a Native C++ Program on the Command Line
I am new to C++ and I am using the free version of Microsoft Visual Studio 2019.
I have written a small code which I use to integrate some differential equations (by using odeint libraries provided by Boost).
After the integration process ends, the time evolutions of the state variables are stored in the matrix mat (I use the Eigen libraries to define it row by row):
MatrixXd mat(t,4);
for (int i = 0; i <= t-1; i++)
{
mat.row(i) << times[i], x_vec[i][0], x_vec[i][1], x_vec[i][2] ;
};
Then I save the content of the matrix in a .txt file:
ofstream file("mat_save.txt");
if (file.is_open())
{ file << mat << '\n'; }
file.close();
However the .txt file is created only if I run the code in Debug mode, while if I only compile it the file is no longer created and no output can be displayed in the Console, since it is only opened when Debug mode is chosen.
Is there a way to make the Console appear and remain open and also to make the .txt file to be successfully saved, simply "compiling" the code avoiding debugging?
If so, I would save lot of time because the debugging is quite slow.
Thanks in advance!!
I'm not sure if by debug you mean running the code in Visual Studio vs compiling and then running the created exe. It Kind of sounds like a relative path issue.
Try using a full path. Or try opening a command prompt, cding to the path with the exe and then running it and check to see if the file is created in the folder you cded to.
You can also try opening the exe in Visual Studio like it was a project. Another thing to try is attaching VS to a running process to debug: http://msdn.microsoft.com/en-us/library/c6wf8e4z.aspx
The Windows Powertool "Handle" can display what handles a process is currently using which could be useful in determining if it is writing a file somewhere unexpected: https://learn.microsoft.com/en-us/sysinternals/downloads/handle
As I often test my binaries inside/outside Microsoft Visual Studio 2017, I want to control the behavior of my code in C/C++ console projects.
One for code for when I run .exe from within Visual Studio in Release mode.
Another when I just click my .exe from Explorer.
What flag or function should I use to know if my .exe was started from inside Visual Studio or not.
What I would like to achive is the:
#if !_RELEASE
system("pause"); // prevents auto shutdown of my .exe in Explorer
// double click
#endif
where _RELEASE is some kind of trait that triggers code in Studio launches,
but not visible in Explorer double click.
What flag or function should I use to know if my process was startded from inside Visual Studio or not.
You shouldn't do such behavior control from inside your program code. That's bad design, and clutters your program code with decisions that should be left on the caller.
I'd recommend if you need different behaviors of your program (e.g. running in background or with visible GUI), this should be controlled with e.g. configuration files or command line parameters.
You can do that for both, Visual Studio settings to specify cmd line parameters, or using a different configuration file, or even a combination of both.
As you seem to insist for a solution of your idea how to fiddle with this in the best way:
You can use the WINAPI functions to iterate through your parent process IDs and check if one of these is matching the "Visual Studio" module.
Here's a Q&A which links to the technique:
How can I reliably check whether one Windows process is the parent of another in C++?
It not exactly solution, but:
Raymond Chen(Microsoft winapi guru*) is most close in spirit to the problem I facing, helping me detect in what mode or circumstances I run my console session.
How can I tell whether my console program was launched from Explorer or from a command prompt?
printf("this process = %d\n", GetCurrentProcessId());
DWORD count = GetConsoleProcessList(nullptr, 0);
if (count == 1) {
printf("I'm the last one!\n");
Sleep(2000);
}
else {
printf("I'm not the last one! %d\n", count);
}
When I run on my working machine (win7 VS2010 ultimate sp1)
int main()
{
unsigned i = 5;
i %= 0;
return 0;
}
or
int main()
{
int * ip = 0;
*ip = 4;
return 0;
}
and I get Integer division by zero unhandled exception. When I hit break button, to see the problem, my Call stack contains only msvcrt100d and ntdll and Visual studio breaks me inside file mlock.c on the LeaveCriticalSection( _locktable[locknum].lock ); line.
When I run this code on another machine(win7 VS2010 proff sp1), VS breaks it exactly on the problematic line i %= 0; od *ip = 4.
This mistake was hidden somewhere within my project and I wasn't able to find it till I run it on another machine. How can I fix this behavior? I need to see it on my working machine.
I have a clean installation of Windows 7, clean installation Visual Studio 2010 and VS-SP1.
My project should not be ruined. I generate it using CMake and same project working fine on non-working machine.
Any advice would be greatly appreciated.
Ok, I have found a solution.
In VS go to exceptions settings (ctrl + alt + e) and check Thrown in required Win32 Exceptions.
More info can be found
here and here.
SO related question here.
When you compile a program with VS it creates the EXE file and a PDB file with all the relevant debugging information of the program. Also, the absolute path of the PDB if embedded into the EXE.
When the EXE crashes and you use VS to debug it, it tries to find the corresponding PDB, both in the same folder than the EXE and in the absolute path embedded in the file. If you want it to be able to debug the program, then you must copy the PDB along with the EXE. Note that these two files must come from exactly the same compilation, or else it will not work.
Then, the VS debugger will try to show you the sources of the program, again using the absolute path of the *.c or *.cpp files embedded in the PDB. Obviously, if you want it to stop in the relevant line, you need a copy of the sources! If you copy the sources to the very same path than in the original machine it should work without problems. If not, you have to open the Call stack window, double-click over the main function and it will ask you to browse for the actual sources.
Or maybe your setup is screwed...
I am trying to work out a simple hello world for OpenCV but am running out of ideas as to why it is not working.
When I compile and run this code:
#include <cv.h>
#include <highgui.h>
int main(int argc, char* argv[])
{
IplImage* img = cvLoadImage( "myjpeg.jpg" );
cvNamedWindow( "MyJPG", CV_WINDOW_AUTOSIZE );
cvShowImage("MyJPG", img);
cvWaitKey(0);
cvReleaseImage( &img );
cvDestroyWindow( "MyJPG" );
return 0;
}
I get a grey box about 200x200 instead of the indicated .jpg file. If I use a different jpg I get the same kind of window, and if I put an invalid filename in, I get a very tiny window (expected).
I am using Visual Studio 2008 under Windows 7 Professional.
Most of the sample programs seem to work fine, so I am doubly confused how that code loads the sample jpgs just fine but in the code above it does not work (even tried the sample jpeg).
Update
The executables produced by compiling work fine, however the Visual Studio 2008 debugger loads a null pointer into img every time I try to run the debugger - regardless if the file location is implicit or explicit.
It really seems like there's a problem with the path to myjpeg.jpg since the current directory could be different when you're running under the debugger.
By default, the current directory that the Visual Studio debugger uses is the directory containing the .vcproj file, but you can change it in the project properties (Debugging -> Working Directory).
Are you 100% sure that you pass the absolute path correctly? Try to pass the same path to fopen and see if it also returns NULL. If so, then the path is incorrect.
If you want to see exactly what file is the library trying to open you can use Project Monitor with a filter on myjpeg.jpg.
Which version of OpenCV are you using? I've tried your code on the latest (OpenCV2.0) and it works fine. You can download OpenCV2.0 from here.
If you want the latest build, you can get check it out with SVN from here.
Try to add HAVE_JPEG into preprocessor definitions.
I encountered the same problem. The Debug version does not load the image, but when I compile and link it as a Release it works. I hope this helps