I am new to programming and seem to be having trouble figuring out how to direct output to a printer.
cout directs to monitor, is there a command to direct to the print queue?
I have a simple console program and am using code blocks for my ide.
A problem like this is dependent on your operating system. Assuming you use windows, you may need to look at the 'Windows API' which may or may not have a method of doing this. Alternatively, you can output to a text file, then use a script to open the file, run through the print menu, and close the file which is less eloquent but will work.
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I have two loggers in my program. One that I made inside a gui, and one that is super complicated but very well designed and prints to the console. I am trying to get the output from the nice console logger to the rendered one. I have tried everything under the sun to get this to work but I can't seem to figure it out (due to my lack of understanding of the code from the other logger(spdlog).) My conclusion is that taking the logs directly from what is printed is the best way to do this but I can't find online anyone asking how to do this. I have seen a few questions but they just post code as an answer and don't really explain what is going on. My question: Is there a way to grab printed statements from the console and what are the performance issues/complications that come with doing something like this.
For example, if i do std::cout << "hello!" << std::endl; or some printf statement, I want to be able to further down in the code be able to grab "hello!"
My conclusion is that taking the logs directly from what is printed is the best way to do this but I can't find online anyone asking how to do this.
Consoles nowadays are terminal emulators. The original terminals' output went to printers and couldn't be (easily) read back.
Application's stdout and stderr (console) streams are write-only. Moreover, in Windows and Unix/Linux you can pipe your program's (console) output (either or both stderr and stdout) into another application with | (pipe) that creates a pipe IPC between stdout of your application and stdin of another one. That IPC pipe is write-only, your application cannot possibly read back from it.
You may be able to get access to the contents of the frame buffer of Windows cmd.exe that controls its Windows console window, but that won't be the verbatim byte-exact copy of data you wrote into stdout because of the escape sequences interpreted by Windows console.
If stdout is redirected into a file you can re-open that file for reading, but there is no portable way to re-open that file.
In other words, there is no portable way to read console output back.
I have tried everything under the sun to get this to work but I can't seem to figure it out (due to my lack of understanding of the code from the other logger(spdlog).
I bet you haven't tried reading spdlog documentation, in particular logger with multi sinks. A sink is an output abstraction, which implementation can write into a file, memory or both. What you need is attach your own sink to spdlog that prints into your UI.
Derive your sink from base_sink and implement abstract member functions:
virtual void sink_it_(const details::log_msg &msg) = 0; to print into the UI, and,
virtual void flush_() = 0; to do nothing.
Then attach one object of your sink class to that spdlog.
I searched the internet, somehow sending documents (txt) to the printer, but not found, how can I do to send TXT files to the printer using the D language?
Like ratchet freak said in the comment, it is the same way you would in C, so if you search for printing text files on Windows and find a C example, you can do it in D too. If a struct or win32 function is not available, you can add it with extern(Windows) and then the function signature. I know you can use a printer like any other graphics device with GDI functions, but that seems harder than it should be, idk if there's an easier way through the win32 API though.
One option: I'm not on a windows box right now, but I'm pretty sure the command print through the shell works on text files too and might be the easiest way. You could use std.file.write to write your string to a text file, then std.process.executeShell to call the print command on that file.
http://dlang.org/phobos/std_process.html#.executeShell
Calling the shell to another command to do it for you might feel hackish, but hey if it gets the job done.
I have a C++ console application that prints some output constantly while it also accepts commands (using std::cin) from the user - output and input happen in separate threads.
If I write a text while some output appears the written text is mixed with application output. How can I prevent this behaviour?
To solve this problem, I need to display the program one line above the line where the text is typed. I'd inspire myself in Minecraft Bukkit server's solution - however I need the same for C++.
Assuming you want the output to appear while things are being typed, you'll need some screen control facilities to have the output go somewhere different than the input area. If I were tasked to implement something like this writing to a terminal I would refresh my ncurses experience. I realize you are on a Windows console and I have no idea if the Windows console is capable of the screen control needed to make it happen.
You can possibly tie custom stream buffers into std::cin and std::cout using the curses functionality under the hood but it may not be worth it. In any case, it isn't entirely trivial.
There's a windows port of ncurses called pdcurses. But if you are using visual studio there's a simple function provided called SetConsoleCursorPosition()
As you can see in u413.com: Text comes on the screen, letter by letter, which looks kind of cool,
I want to do the same thing in Console
I got the source code of version 1.2; because I dont need all the complexity of version 2;
I just need a simple Command Prompt, with text that comes on to the screen letter by letter.
I dont need most of the builtin functions offered by Console, like Transparency, Taskbar Icon, etc.
The source code base is pretty small with only about 5 files.
The main class file seems to be Console.cpp;
Since console is like a GUI application, things dont get written to the STDOUT.
but heres what happens;
A Handle is called;
And that handle apparently writes to the console;
m_hStdOut = ::GetStdHandle(STD_OUTPUT_HANDLE);
Now what I want to be able to do; Is somehow read the handle; see what text it has; And throw in a loop with a ::Sleep(20) method in it; to make sure that text appears letter by letter.
#Alf P. Steinbach I wrote the psuedo code for making the sleep command(in java) I also made use of it in every other java program I wrote, but the disadvantage was that it will work only for my programs and not every program run in the command prompt, but what I dont know is code to make a console, a windows console subsystem program, I wish it was possible with java, so that I could use it on linux too, but now, let me ask you exactly what I had in mind...
A program which simply, took input from the screen, send it to cmd.exe for processing, and sent back the reply, and all I have to do is throw in a sleep command between every character...
All I need is help, in getting this done, I wish you could start me up with this, and possible provide links and refrences to get this done...
This Console.cpp seems like a console emulator, meaning it runs OTHER programs. You don't need the source code, you can run existing console applications.
STD_INPUT_HANDLE, STD_OUTPUT_HANDLE and STD_ERROR_HANDLE are the windows handles for STDIN, STDOUT and STDERR. They basicly does the same with only a few differences in how to use it.
If you want to integrate the console into your code, then you have to understand it, and find its own output function and call that. But it won't be any standard handle or things like that.
I wish to use the functions of autohotkey within a C++ program.
I am currently running my scripts triggered by the c++ program- I just run them as a .bat file. This works well but the problem is that I cannot return values from the script to the c++ program.
I wish to be able to read the position of the mouse from the script and make decisions based upon this in my C++ program. My scripts do quite complex things- so doing this in autohotkey is the best solution for me- I have knowledge of C, but little of C++.
I have read about the Autohotkey .DLL - I know how to trigger it but not how to read values from it. If anyone could instruct me or even post example code of a .dll being loaded and a value sent to a script and a value returned- I would be eternally grateful!!
I have spent hours on this and to no avail!
to return a value, could this possibly work http://www.autohotkey.net/~tinku99/ahkdll/functions/ahkgetvar.htm
I'm not sure about the dll, but you could just write your own application in Autohotkey and package it along with your C++.
The communication takes place over a hidden window with an edit control and a button. You use one application to set text in the edit box, and then to click the submit button. The other application owns the window can process whatever is put into the edit control - as if you were passing a variable. Basically, that's it.
Check out this thread where I've explained it in more detail: How to send a command to a running application via commandline
Now, that's not quite what you wanted, but the effect is the same, and you already know all the api.