i was working in multimedia applications, and i know system() is a library call and "sync" is a Linux command which invokes sync(2) system in direclty. i need to know what happens exactly, while system("sync"); get executed
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I wish to know what tools my IDE runs and what command line arguments it uses.
Is there such tool that will provide such information?
I can make an app that will save all processes every second or even faster but I'm still not sure that it will hook everything. There must be some tool already that will do that work much better. Like hooking OS calls for WinExec or CreateProcess(Ex).
Sysinternals Process Monitor can log process events, among other things. It works by monitoring Native API calls, so it'll work regardless of which library function programs use.
I currently have a resource light "unmanaged" Windows C++ application using:
CreateMutex to ensure there is at most a single instance of the application.
COPYDATASTRUCT to pass command line parameters over to that single instance, should another instance attempt to start (after sending data, it will then quit).
The use case is a simple one: launch a new application instance to open a file specified on the command line, or otherwise open the file in a previously-launched application instance.
How could I achieve the same behaviour in a Haskell program?
It looks like CreateMutex isn't offered in the Win32 package that comes with GHC. You'll need to either bind to it yourself using the FFI or emulate it in a cross-platform way. One trick commonly used on Linux is to choose a particular filename to act as the "mutex"; if it doesn't exist, you create it and write down how to contact you then delete it when you exit, while if it does, you read the contact information out of it to find out how to connect to the already running process. This approach does have downsides: if either your app or the computer as a whole goes down, you'll have stale contact information.
For IPC, I think there's a number of cross-platform interfaces. Wikipedia has an excellent list; especially suitable for doing this task in Haskell are sockets, (named) pipes, and dbus. For the latter two, you may need Cygwin, since they ultimately depend on getting the unix package installed.
I am from Unix programming background and am facing a unique behavior/problem during porting my system from Unix to Windows.
[I am pretty new to development on windows, so the below question may look too obvious.]
I am porting using mingw and the problem in question is regarding "system()" call provided in Unix and the WEXITSTATUS option.
Question
In Unix, to execute any commands/scripts we have code that uses system() call. The same compiles in mingw - but I want to know if there are any change in behavior between the Unix and Windows version of system() call.
The windows version of system() call is provided in stdlib of mingw, but am not able to get the exact behavior.
My second question is regarding WEXITSTATUS. Generally, In Unix this is used along with system() command to get the status of the command executed.
a. Can the same be done with system() of stdlib of mingw?
b. How to achieve it?
Note :
I have read about createProcess and its subsequent usage in the net - But my idea is to continue with existing code (use system() call itself) and find an alternative to WEIXTSTATUS.
Thanks for your help/suggestion in advance.
Look here for Win32 documentation on system: http://msdn.microsoft.com/en-us/library/277bwbdz%28v=VS.100%29.aspx
Note that the system call is subject to the command interpreter on the system, and cmd.exe (Windows command interpreter) works differently than Unix Bash.
I am porting an application which runs as a background service in windows at startup, we are porting the application to linux(SUSE Enterprise server), I'am completely new to linux. Can somebody help me on how to proceed with this. Like
Should I build the linux executable
After builiding the binary, what changes should I make to linux startup files to run this executable
How my service can register call back function to modify or change or send commands to my service while it is running
Yes, you should build a Linux binary. You may want to rephrase your question since I doubt this is the answer you want :-)
You should generally create what is known as an "init" file, which lives in /etc/init.d. Novell has a guide online which you can use to author the file. Note that while the init file is common, the exact method of letting the operating system use it varies depending on the distribution.
This is going to be a marked change for you. If you are doing simple actions such as re-loading a configuration file, you can use the signals functionality, especially the SIGHUP/HUP signal which is generally used for this purpose. If you require extended communication with your daemon, you can use a UNIX domain socket (think of it as a named pipe) or a network socket.
Another task you are going to need to accomplish is to daemonize your application. Generally this is done by first fork()ing your process, then redirecting the stdin/stdout pipes in the child. There are more details which can be answered by reading this document
See how-to-migrate-a-net-windows-service-application-to-linux-using-mono.
Under Linux, deamons are simple background processes. No special control methods (e.g start(), stop()) are used as in Windows. Build your service as a simple (console) application, and run it in the background. You can use a tool like daemonize to run a program as a Unix daemon.
I guess it is impossible, but I will ask it anyway. I have a Windows application that executes BeginUpdateResource / UpdateResource / EndUpdateResource
Can I somehow execute this on Linux/Unix? Its server-side, so no GUI emulator could be running.
I am not sure exactly what can be achieved with Wine, but that might be a way to go if you have the source code for the application you want to run. See also Will Wine run only under X, or can it run in character mode?.
Another alternative is to re-write the functionality.
I would not recommend it unless you are using Wine which is not an emulator but a re-implementation/binding of the Win32 API on Linux and a handler for Windows executables.
If you want to do things like this, port your application to C#/.NET and use the Mono runtime on the Linux system..
In short, dont