I find there is no daytime server available in leopard/snow leopard. And after reading some documents, the approach I can think of is writing a daemon and put it under /System/Library/LaunchDaemons, so that launchd can run it. I wonder if there is a way to just enable the service rather than writing a new one myself?
Thanks in advance!
Tianzhou
Please see my other answer.
It does mean you have to write one yourself but will hopefully streamline the process.
Related
I am writing a client-server in C in which many clients send a running file to server and server needs to execute the file and save the result in their computer.
now I have 2 questions:
1-should server save the receiving file before executing it?if yes how?
2-I am going to use CreateProcess() function to make a child and run every clients file in different process..is that a good choice?!
thank you for your kind help in advance
Negar
1.) Yes. And if you are asking this, you probably doesn't have the knowledge to run executables in-memory.
2.) CreateProcess() enable the host (your server app) to share handle with the child (spawned app).
This is helpful if you want to know the child's console output.
1) Yes, probably a good Idea if want to build some resilience in your server at later point.
2) Yes again, apart from the reasons outlined by YeenFei for security and robustness perspective. As the executable received from the client might crash and you do not want your server process to crash along with it.
Is there a way i can send a notification/message to another PC in C/C++? I think something like net send, but i don't know if there is another way to send a notification/message. I created an application which will run on every PC, and i want, that if my application has finished it should send a notification to my PC, that it has finished running. I don't know if there is a solution for my question, but if yes, could someone tell me, how to do that?
Thanks,
kampi
How about using sockets?
http://www.alhem.net/Sockets/tutorial/
Start by learning about WCF. http://msdn.microsoft.com/en-us/netframework/aa663324.aspx
We ended up building a system for alerting all of our retail locations of emergency situations by building a service that opens up a TCP channel using .NET Remoting. It just sits there and listens for notifications. Our command center has a program that can send out notifications to this service. The service is responsible for displaying the message.
The code is proprietary, so I can't share it, but that's the general idea. Remoting has been rolled into WCF, which is why I started by suggesting learning that.
It has been working very well for us for many years, and works just fine on newer versions of Windows (unlike Net Send) and it's faster than Net Send.
Edit - added
I hadn't heard of this until now but you could also look into msg.exe. it looks easier.
http://www.appscout.com/2009/03/vistas_msgexe_replaces_net_sen.php
If you want something like "NET SEND" use mailslots!
Here more info on MSDN: http://msdn.microsoft.com/en-us/library/aa365576.aspx
If you can't use net send, how about just creating a date-stamped temp file of some sort that your other PC looks for?
Make your application a Growl client
Net Send is an option, but I think it will annoy the crap out of you, as it sends console toast to your computer, which pops up in front of the tasks you are working on. Personally, I would find that incredibly annoying.
If you created the application, you have the ability to include notication code. As an example, you can set up a service on your box and write the code to contact that service. On a windows machine, this can be a WCF service. You can also wrap this in a windows service if you want to fire up non-annoying toast.
I am not sure how to set up C to access a service, so another option might be to drop something in a folder and have a file watcher tell you. A bit kludgy, of course.
I want to make a program that reads a serial port (V.24).
with the info from the serial port I need to split a string up, and add it to a MySQL database.
I don't know C very well, so I need some help with what functions I should use
The program has to run under windows XP, and I have to make it an service.
thanks,
Sebastian
Services are a pain to debug. I suggest writing your code as a normal application first - command line will do - and then, once it works, converting it to a service (which is a mechanical process).
In general, Windows GUI based apps in C are a PITA to write for the first time. Very finicky, very sensitive. A command line app or a service will be quite a bit easier.
I recommend reading this. As for if this will work as a service, I am not sure, but it should.
You can also look at existing open source projects, to see if you can take that source as a starting point, or if they already solve your problems.
I am trying to write a simple program, preferably in C, that will watch a given directory. Whenever a process accesses that directory, I just want to print out the name of that process. It seems simple, but I am coming up short for solutions on MSDN. Does anyone know which library calls I will need for this, or any helpful advice? I have considered repeatedly querying for what processes have handles on the given directory and just watching for additions to that list.This approach just seems very intensive and I am hoping there is an easier way. Thanks.
I'm not sure if there's an easier way, but one way is to use a file system filter driver. Or easier a file system minifilter driver.
You can filter, log, track, control, ... all IO.
There is no supported way to do this from user mode. You can use the FindFirstChangeNotification API to tell when a file or directory has changed, but that doesn't tell you who did it. You might be able to hook some things to obtain this information... but that is of course not supported.
If you can use a driver, you can use Event Tracing for Windows for this information. This is what Sysinternals ProcMon uses. But installation of a driver is a very invasive process, bugs in your driver cause BSODs, and installation of a driver requires administrative rights. Something to keep in mind.
If it's possible, I'm interested in being able to embed a PostgreSQL database, similar to sqllite. I've read that it's not possible. I'm no database expert though, so I want to hear from you.
Essentially I want PostgreSQL without all the configuration and installation. If it's possible, tell me how.
Run postgresql in a background process.
Start a separate thread in your application that would start a postgresql server in local mode either by binding it to localhost with some random free port or by using sockets (does windows support sockets?). That should be fairly easy, something like:
system("C:\Program Files\MyApplication\pgsql\postgres.exe -D C:\Documents and Settings\User\Local Settings\MyApplication\database -h 127.0.0.1 -p 12345");
and then just connect to 127.0.0.1:12345.
When your application quits, you can always send a SIGTERM to your thread and then wait a few seconds for postgresql to quit (ie join the thread).
PS: You can also use pg_ctl to control your "embedded" database, even without threads, just do a "pg_ctl start" (with appropriate options) when starting the application and "pg_ctl stop" when quitting it.
You cannot embed it, nor should you try.
For embedding you should use sqlite as you mentioned or firebird rdbms.
Unless you do a major rewrite of code, it is not possible to run Postgres "embedded". Either run it as a separate process or use something else. SQLite is an excellent choice. But there are others. MySQL has an embedded version. See it at http://mysql.com/oem/. Also several java choices, and Mac has Core Data you can write too. Hell, you can even use FoxPro. What OS you on and what services you need from the database?
You can't embed it as a in process type thing like sqlite etc, but you can easily embed it into your application setup using Inno setup at http://www.innosetup.org. Search their mailing list archive and you will find someone did most of the work for you and all you have to to is grab the zipped distro and you can easily have postgresql installed when the user installs your app. You can then use the pg_hba.conf file to restrict the server to local host only. Not a true embedded DB, but it would work.
PostgreSQL is intended to run as a stand-alone server; it's probably possible to embed it if you hack at it hard and long enough, but it would be much easier to just run it as intended in a separate process.
HSQLDB (http://hsqldb.org/) is another db which is easily embedded. Requires Java, but is an excellent and often-used choice for Java applications.
Anyone tried on Mac OS X:
http://pagesperso-orange.fr/bruno.gaufier/xhtml/prod_postgresql.xhtml
http://www.macosxguru.net/article.php?story=20041119135924825
(Of course sqlite would be my embedded db of choice as well)
Well, I know this is a very very very old post, but if anyone has nowadays this question, I would refer to:
You can use containers running Postgres. Here's a post that could be helpful, doing something along this line using R:
https://rsangole.netlify.app/post/2021/08/07/docker-based-rstudio-postgres/?utm_source=pocket_mylist
Take a look at duckdb https://duckdb.org/docs/installation/ It is relatively new and still needs to mature. But it works pretty much like an embedded database ("In-process, serverless"), with bindings for several languages (Python, R, Java, ...)