C / C++ / MFC

Re: How to redirect WriteFile func writes to console

19-Feb-18 6:19

Okay so this spawns the thread before it executes the command passed in.
It should spit the console even if the command doesn't terminate, which I still find strange.

#include <stdio.h>
#include <iostream>
#include <windows.h>
#include <tchar.h>

FILE* OutStream;
FILE* InStream;
FILE* ErrStream;

struct execData {
	TCHAR* CmdLine;
	TCHAR* CmdRunDir;
	PROCESS_INFORMATION  process_info;
	STARTUPINFO  startup_info;
};

struct execData		 data = { 0 };

/*---------------------------------------------------------------------------
Application handler.
---------------------------------------------------------------------------*/
LRESULT CALLBACK GUIDemoHandler (HWND Wnd, UINT Msg, WPARAM wParam, LPARAM lParam) {
	switch (Msg) {
		case WM_CREATE:
			AllocConsole();  //Allocate a console
			freopen_s(&InStream, "CONIN$", "r", stdin); // Redirect standard in
			freopen_s(&OutStream, "CONOUT$", "w", stdout);  // Redirect standard out
			freopen_s(&ErrStream, "CONOUT$", "w", stderr);  // Redirect standard error
			break;
		case WM_DESTROY:											// WM_DESTROY MESSAGE
			if (data.process_info.hProcess) TerminateProcess(data.process_info.hProcess, 0);
			FreeConsole();
			PostQuitMessage(0);										// Post quit message
			break;

		default: return DefWindowProc(Wnd, Msg, wParam, lParam);	// Default handler
	};// end switch case
	return 0;
}

DWORD WINAPI ExecThreadFunction(LPVOID lpParam)
{
	int  Success;
	struct execData* data = (struct execData*)lpParam;
	Success = CreateProcess(
		nullptr,
		data->CmdLine,
		nullptr,
		nullptr,
		TRUE,
		0,
		nullptr,
		data->CmdRunDir,
		&data->startup_info,
		&data->process_info
	);

	if (!Success) {
		CloseHandle(data->process_info.hProcess);
		CloseHandle(data->process_info.hThread);
		return -4;
	}
	else {
		CloseHandle(data->process_info.hThread);
	}

	WaitForSingleObject(data->process_info.hProcess, INFINITE);

	CloseHandle(data->process_info.hProcess);
	
	data->process_info.hProcess = 0;
	return (0);
}



int SystemCapture(
	TCHAR*         CmdLine,    //Command Line
	TCHAR*         CmdRunDir)  //set to '.' for current directory
{
	SECURITY_ATTRIBUTES  security_attributes;             

	data.CmdLine = CmdLine;
	data.CmdRunDir = CmdRunDir;
	security_attributes.nLength = sizeof(SECURITY_ATTRIBUTES);
	security_attributes.bInheritHandle = TRUE;
	security_attributes.lpSecurityDescriptor = nullptr;
	data.startup_info.cb = sizeof(STARTUPINFO);
	data.startup_info.hStdInput = 0;
	data.startup_info.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
	data.startup_info.hStdError = 0;
	data.startup_info.dwFlags |= STARTF_USESTDHANDLES;

	CreateThread(NULL, 0, ExecThreadFunction, (LPVOID)&data, 0, NULL);
	
	return 0;
}



const TCHAR* ClassName = _T("GUI_CONSOLE_APP");

/* ------------------------------------------------------------------------
   The application entry point
   -----------------------------------------------------------------------*/
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow){
	MSG Msg;
	HWND Wnd;

	WNDCLASSEX WndClass = { 0 };
	WndClass.cbSize = sizeof(WNDCLASSEX);							// Size of this record
	WndClass.style = CS_OWNDC;										// Class styles
	WndClass.lpfnWndProc = &GUIDemoHandler;							// Handler for this class
	WndClass.cbClsExtra = 0;										// No extra class data
	WndClass.cbWndExtra = 0;										// No extra window data
	WndClass.hInstance = GetModuleHandle(NULL);						// This instance
	WndClass.hIcon = LoadIcon(0, IDI_APPLICATION);					// Set icon
	WndClass.hCursor = LoadCursor(0, IDC_ARROW);					// Set cursor
	WndClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);	// Set background brush
	WndClass.lpszMenuName = NULL;									// No menu yet
	WndClass.lpszClassName = ClassName;								// Set class name
	RegisterClassEx(&WndClass);										// Register the class				
   	Wnd = CreateWindowEx(0, ClassName, _T("GUI Console Demo Program"), 
		WS_VISIBLE | WS_OVERLAPPEDWINDOW, 
		50, 50, 500, 400,
		0, 0, 0, NULL);												// Create a window

	_tprintf(_T("This will go to the console\r\n"));
	std::cout << "Second line to console\r\n" << std::endl;

	int            rc;
	TCHAR szCmdDir[256] = _T(".");
	std::cout << "\r\nExecute console app:" << std::endl;
	TCHAR szCmdLine1[256] = _T("ConsoleApp.exe");    // You strange non terminating app
	rc = SystemCapture(
		szCmdLine1,								 //Command Line
		szCmdDir                               //CmdRunDir
	);

 	while (GetMessage(&Msg, 0, 0, 0)){								// Get messages
		TranslateMessage(&Msg);										// Translate each message
		DispatchMessage(&Msg);										// Dispatch each message
	};
	return (0);
}

I made a strange console app that just spins the cursor to test it worked which was called ConsoleApp.exe hence my name above

static const char Spin[4] = { '|', '/', '-', '\\' };



int main()
{

	int i = 0;
	while (1) {
		printf("Deadloop %c\r", Spin[i]);
		for (long j = 0; j < 10000000; j++) {};
		i++;
		i %= 4;
	}

    return 0;
}

In vino veritas

modified 19-Feb-18 13:37pm.

Łukasz Gęsieniec19-Feb-18 9:06

Re: How to redirect WriteFile func writes to console

19-Feb-18 9:06

I am checking it using test app with WriteFile function and it works. But I will check it using target app tomorrow because it needs some hardware to work.
Thanks

Łukasz Gęsieniec19-Feb-18 19:53

Re: How to redirect WriteFile func writes to console

19-Feb-18 19:53

This code is working.
Now I will try to analyze outputs and build GUI.
I am not sure if can I use the code in C# WPF application. If not I will try to build GUI using Win API starting from your examples. Thank you.

leon de boer19-Feb-18 20:14

Re: How to redirect WriteFile func writes to console

19-Feb-18 20:14

It's a simple background worker thread it will work without issue in a C# WPF application.

How to: Use a Background Worker[^]

Inside the worker thread you want a standard command execute

static void runCommand() {
    //* Create your Process
    Process process = new Process();
    process.StartInfo.FileName = "cmd.exe";
    process.StartInfo.Arguments = "/c yourfile.exe";
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.StartInfo.RedirectStandardError = true;
    //* Set your output and error (asynchronous) handlers
    process.OutputDataReceived += new DataReceivedEventHandler(OutputHandler);
    process.ErrorDataReceived += new DataReceivedEventHandler(OutputHandler);
    //* Start process and handlers
    process.Start();
    process.BeginOutputReadLine();
    process.BeginErrorReadLine();
    process.WaitForExit();
}
static void OutputHandler(object sendingProcess, DataReceivedEventArgs outLine) {
    //* Do your stuff with the output (write to console/log/StringBuilder)
    Console.WriteLine(outLine.Data);
}

In vino veritas

modified 20-Feb-18 2:21am.

Łukasz Gęsieniec19-Feb-18 22:34

Re: How to redirect WriteFile func writes to console

19-Feb-18 22:34

I do simple test and problem is the same as before. Only when console app quits OutputHandler is executed and then I can read every line by line that app prints during running. Furthermore, it seems that StandardInput is not redirected because click on the button does not quit the app. App quits when 'e' key is pressed in the console window.

public partial class MainWindow : Window
{
    Process process = new Process();

    public MainWindow()
    {
        InitializeComponent();
        runCommand();
    }

    private void button_Click(object sender, RoutedEventArgs e)
    {
        textBox.Text += "test\r\n";
        process.StandardInput.Write('e');
    }

    void runCommand()
    {
        //* Create your Process

        process.StartInfo.FileName = "c:\\ConsoleApp.exe";
        process.StartInfo.Arguments = ".";
        process.StartInfo.UseShellExecute = false;
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.RedirectStandardError = true;
        process.StartInfo.RedirectStandardInput = true;
        //* Set your output and error (asynchronous) handlers
        process.OutputDataReceived += new DataReceivedEventHandler(OutputHandler);
        process.ErrorDataReceived += new DataReceivedEventHandler(OutputHandler);

        //* Start process and handlers
        process.Start();
        process.BeginOutputReadLine();
        process.BeginErrorReadLine();
        //            process.WaitForExit();
    }
    void OutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
    {
        //* Do your stuff with the output (write to console/log/StringBuilder)
        Console.WriteLine(outLine);
    }
}

leon de boer20-Feb-18 6:18

Re: How to redirect WriteFile func writes to console

20-Feb-18 6:18

Yes because you didn't put it in a worker thread Smile | :)

You need runCommand() to be in a worker thread .. it has to execute in the background so you can keep the WPF framework running in the foreground.

Look back at the windows code I had to do the same thing the CreateProcess(...) is inside a function which is spawned into it's own thread via CreateThread.

Unfortunately I don't use C# enough to know the code for making a worker thread off the top of my head.
I actually don't have the WPF framework installed on my VisualStudio at the moment to work it out.

Basically however we can describe it
1.) everything in runCommand() needs to go inside the worker thread start function .. when the thread starts it runs the app
2.) When the app finishes or your WPF app finishes you need to close the worker thread (LOOK at WM_DESTROY on the windows code)

So basically this worker thread will be chugging along in the background running the app but your program comes back to you to continue on to run the WPF framework.

So you job is to work out how to make a WPF worker thread and incorporate the code Smile | :)

In vino veritas

leon de boer20-Feb-18 6:33

Re: How to redirect WriteFile func writes to console

20-Feb-18 6:33

If you want a total guess looking at the MSDN reference and your code but ignoring the exit problem Wink | ;-)

using System.Threading;
new Thread(() => 
{
    Thread.CurrentThread.IsBackground = true; 
    runCommand();
}).Start();

Łukasz Gęsieniec20-Feb-18 23:32

Re: How to redirect WriteFile func writes to console

20-Feb-18 23:32

Running runCommand() from new Thread didn't help. I can read all outputs after console app quits.
It is harder to build GUI using WinAPI than using WPF but WinAPI code works.

leon de boer21-Feb-18 7:12

Re: How to redirect WriteFile func writes to console

21-Feb-18 7:12

Okay the problem is console.writeline is blocking

C# test.net » Using Process.Start to capture console output[^]

.net - Does Console.WriteLine block? - Stack Overflow[^]

You can use one of the methods or Console.Out.WriteLineAsync("..."); if available.

For us old timers it's actually faster to build a GUI with the API than with the WPF framework Smile | :)

In vino veritas

modified 21-Feb-18 20:03pm.

Łukasz Gęsieniec21-Feb-18 19:57

Re: How to redirect WriteFile func writes to console

21-Feb-18 19:57

OK, I know what you mean Smile | :)

For me, it is easier to use WPF because I am embedded system engineer.
I am from embedded world and I do not know Windows internals.
That is why I am asking a lot of (stupid) questions. After reading several articles I supposed that redirect output and develop GUI app should be easier Smile | :)

Now I know that my strange console app does not use standard printf function Cry | :((

leon de boer22-Feb-18 14:19

Re: How to redirect WriteFile func writes to console

22-Feb-18 14:19

The obvious question is can you not simply replace the program communicating with a proper windows code or is it a private format they won't disclose. Just saying it would be faster, cleaner and less code than what you are doing now Smile | :)

In vino veritas

Łukasz Gęsieniec22-Feb-18 19:50

Re: How to redirect WriteFile func writes to console

22-Feb-18 19:50

Yes, it is a private closed format.
Another way to communicate with the console app is passing command line arguments:

MyApp.exe -Iinput.txt -Ooutput.txt

where in the input.txt file in each line is a key command (e - exits the program, other keys do some actions):
l
f
m
c
o
e
in the output.txt file, the program saves its output. Even something like this works:
MyApp.exe -OCON - prints output to console twice.
But problem is the same. If I monitor the output file, the content appears after app quits (e command in input file)

Peter_in_278022-Feb-18 20:21

Peter_in_2780

22-Feb-18 20:21

This smells to me of buffering. I'm guessing your app doesn't call flush() or equivalent on its output file, so the output is buffered until the explicit or implicit close() call at termination.
If you can make your app output lots of data, you will probably see it appear in chunks, which will be whatever buffer size is used.
The reason it works on the console is that console drivers do not buffer.
I have no idea if you can suppress buffering in your redirection, but if you could, my 2c says that would solve your problem.

Good luck!
Peter

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Re: How to redirect WriteFile func writes to console

leon de boer22-Feb-18 21:06

problem defining a function inside a structure in c

22-Feb-18 21:06

Yes standard console output is always buffered.
You can actually easily remove it

setvbuf(stdout, NULL, _IONBF, 0);
setvbuf(stderr, NULL, _IONBF, 0);

The problem is it will slow the console program down like a dog as each character invokes a full call.

I sometimes do it when I have a embedded target with UART debugger like on the Raspberry Pi.

In vino veritas

Member 1367832014-Feb-18 5:40

Member 13678320

14-Feb-18 5:40

my code is:
#include<stdio.h>
#include<conio.h>

struct point
{
int x,y;
void getdis()
{
printf("%d",x+y);
}
};

int main()
{
struct point p;
int a=5,b=10;
p.getdis(a,b);
getch();
return 0;

}

problem is:8 2 F:\software\Dev-Cpp\bin\point.c [Error] expected ':', ',', ';', '}' or '__attribute__' before '{' token
I cannot understand what to write before the getdis function to avoid this error

suman chandra modak

Re: problem defining a function inside a structure in c

David Crow14-Feb-18 6:09

David Crow

14-Feb-18 6:09

void getdis()
...
p.getdis(a,b);

These two do not match. Hint: they should.

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles

Re: problem defining a function inside a structure in c

CPallini14-Feb-18 10:44

CPallini

14-Feb-18 10:44

methods are a C++ feature you can only mimic in C, suing function pointers and the like. For instance

#include<stdio.h>
struct point
{
  int x,y;
  void (*pfun)(struct point *pp);
};

void getdis(struct point *pp)
{
  printf("%d\n", (pp->x + pp->y));
}

int main()
{
  struct point p;
  p.x = 5; p.y = 10;
  p.pfun = getdis;

  p.pfun(&p);

  getchar();
  return 0;
}

setting Boundary condition X^2-Y^2 for solving Laplace equation for NxN grid.

Member 1362564310-Feb-18 17:23

Member 13625643

10-Feb-18 17:23

i am trying to write a code to solve Laplace equation using Successive

Python

Over relaxation(SOR)on a NXN matrix
boundary condition is X^2-y^2
i dont know how to set this boundary condition on the Mesh created by me

here is the code

import numpy as np
from pylab import *
import sys
import copy
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
L =[[]for i in range(2)]
N=int(input("Enter a number N for N x N grid: "))
h=1/N
def clear_list1():
    L[1].clear()
    L[0].clear()
iterat=0
error=0.75
clear_list1()
xx=np.arange(0,N,h)
yy=np.arange(0,N,h)
x,y = np.meshgrid(xx,yy)
phi= copy.deepcopy((x**2-y**2))
phi[1:-1,1:-1]=0
phi_new = copy.deepcopy(phi)
resid=np.zeros((N,N))


while True:
    if iterat<21:

       for w in np.linspace(1,2,11):
           for i in range(1,N-1):
               for j in range(1,N-1):
                   phi1=(phi[i+1,j]+phi[i-1,j]+phi[i,j+1]+phi[i,j-1])/4
                   phi[i,j]=w*phi1+(1-w)*phi1
                   
       Sumresidual=0
       for i in range(1,N-1):
           for j in range(1,N-1):
               resid[i,j]= -4*phi[i,j]+phi[i+1,j]+phi[i-1,j]+phi[i,j+1]+phi[i,j-1]
               Sumresidual=Sumresidual+(resid[i,j])**2
    else:
        break
    iterat=iterat+1
    p=np.sqrt(Sumresidual)
    L[0].append(p)
    L[1].append(w)

ax = plt.axes()
ax.xaxis.set_major_locator(ticker.MaxNLocator(5))

plt.plot(L[0],L[1])
plt.yscale('log')
plt.xlabel('w')
plt.ylabel('|| residual ||')
plt.title('effect of w on residual')
plt.show()

Re: setting Boundary condition X^2-Y^2 for solving Laplace equation for NxN grid.

Victor Nijegorodov10-Feb-18 23:07

Victor Nijegorodov

10-Feb-18 23:07

And what does your code have to do with the C / C++ / MFC Forum?

Default Stack Size

ForNow10-Feb-18 17:02

ForNow

10-Feb-18 17:02

hi
I was getting storage overlays in my local variable when I noticed that the SP register was 0X4652E25F0 and my BP registers was 0X4C652E2A60 does that mean that my stack size is 144 bytes

I have a table in the function itself that is 256 bytes to translate ASCII to EBCDIC

beginthread stack size is 0

Richard MacCutchan10-Feb-18 21:23

Richard MacCutchan

10-Feb-18 21:23

Quote:
In addition, the stack_size argument can be 0, in which case the operating system uses the same value as the stack that's specified for the main thread.

Don't try to guess what the situation may be just by looking at registers. In most code BP is set as a base register from an offset of SP, but that does not imply any particular stack size.

ForNow11-Feb-18 3:55

ForNow

11-Feb-18 3:55

I guess it could be set /F compiler option thanks

Richard MacCutchan11-Feb-18 6:32

Richard MacCutchan

11-Feb-18 6:32

ForNow wrote:
I guess it could be ...

... anything. Guessing is not generally a good strategy for fixing problems. You need to be sure what the problem is first. Maybe if you show the code where the problem occurs, and a few more details, we could make some useful suggestions.