How to make a linux command-line program work in windows? - c++

Question

I'm a beginner with programming, and I've been doing work in C/C++ in Ubuntu. When I tell something to cin/cout/cerr or printf/scanf or take arguments from the command line, this all happens from the linux terminal in Ubuntu.
Now if I want to run these same programs (very simple programs, beginner-level) and run them in Windows, how do I run them from the Windows command line? A previous course I've taken had us download cygwin to simulate the linux command line in windows, but what if I want to just run the program from the ordinary windows command line? Is that possible, and does it require modification of the software?

Answer 1

You can cross-compile the program for Windows from linux.
On Ubuntu, process is basically this:
sudo apt-get install wine mingw32 mingw32-binutils mingw32-runtime
...
i586-mingw32msvc-g++ -o myProgram.exe myProgram.cpp
Easy, right? Google for "ubuntu cross-compile windows," there's a ton of information out there.

Answer 2

It's exactly the same. You run cmd and write the command (almost) exactly as you would in Linux.
For example, if you build your program to program, you would run it in Linux like this:
./program --option1 -o2 file1 file2
And in Windows, first you have to make the output have a .exe suffix and then in cmd you would write:
program.exe --option1 -o2 file1 file2
Basically saying, cmd is Windows' terminal. It's nowhere near as good as the Linux terminal, but that would be all you get without installing additional software.
cin/cout/cerr and printf/scanf/fprintf(stderr, ...) use the standard C preopened files stdin, stdout and stderr which are defined both in Linux and Windows. Once you run the application from Windows' terminal (cmd), you see the input/output exactly as you would in the Linux terminal. I/O redirection is also very similar.

Answer 3

cin and cout, and printf and scanf, work much the same in Windows as they do in Linux. (I'm pretty sure cerr does too, but that one i'm not 100% sure about. At the very least, though, it's there and works.) The biggest difference is that Windows typically won't expand wildcards (stuff like *.txt) before running your program; you have to do that yourself in most cases.
Basically, as long as the app doesn't use anything specific to Linux or GCC, you could just recompile it on the target machine using whatever compiler you like to test.
If you don't want to recompile...well...good luck with that. Even Cygwin won't run native Linux binaries. You'd need a virtual machine with Linux on it.

Answer 4

Well, if you program is portable and not using any features specific to Linux, you would have to compile it from source on Windows to make it work on Windows.
You would need the GCC tool-chain for windows to do that, which you can get from the TDM-GCC homepage. Its MinGW internally and the installer allows you to choose the features you want to install as well as the target directory for installation. It also adds itself to Windows path so that the compiler commands are available from the shell prompt.
I have to do the cross compilation regularly and it works without any issues for me. There is one change which you must make if your project is using Makefiles. For the target binary, such as <target>.out in linux, you would have to edit your Makefile and rename it to <target>.exe so that it runs on the command line. If you are not using Makefiles and just doing gcc <file.c>, the a.exe is produced by default (similar to a.out in Linux).

Answer 5

Say you have this program code you want to run on UNIX and Windows:
#include <stdio.h>
int main()
{
printf("Hi\n");
return 0;
}
When you type a command in a UNIX shell it will be something like this.
/usr/home/bobby# gcc main.c
/usr/home/bobby# ./a.out
Hi
/usr/home/bobby#
On Windows you'd have to first choose your development environment/compiler. Without going to something like Cygwin, you could install the Windows SDK or Visual studio (although if the latter you might just want to develop in the GUI).
Start -> Run -> cmd /k ""C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\vcvarsall.bat"" x86
C:\Windows\system32>cd c:\bobby
C:\bobby>cl main.c
C:\bobby>main.exe
Hi
C:\bobby>

Answer 6

When a C program is compiled into an executable this is done in a system dependent way. On Ubuntu the ELF format is used and on Windows we have PE.
When you start a process the ELF or PE is read giving instructions/map on how to allocate memory and where to put various pieces of the process in a virtual memory table. Further it links up to dynamically loaded libraries, already in physical memory, that it share with other processes which is using the same libraries. Or if the dynamic libraries is not present load them. (Linux .so, windows .dll). If it has static libraries these are allocated and linked in (Linux .a, Windows .lib). - Very simplified.
Memory restrictions etc are inherited from previous process.
Environment variables are put into the running environment for the process. This being paths, arguments, etc. Then main() is added to the stack and called.
Now everything happening before main is called and how linkage etc are resolved, and so many other things, depends on the system. This is why one simply can't run an executable compiled on Linux on Windows.
Using cygwin one is simply creating a virtual environment where those linkages etc are the same and would work. One create an ELF environment.
To get it linked for native Windows command line one would have to compile for Windows. On that matter I see there is lots of answers already.
The ELF and PE, as on different systems, also have different ways of handling environment variables etc. What these are etc. So i.e. file expansion is handled differently. However both running processes has the default streams like stderr, stdout and stdin. But below your code in C they are not the same.
It is like driving a diesel vs a petrol car. Much is the same but under the hood quite a few things is different.
Be aware that i.e. signals are handled different on Windows.