Hello,
Does anyone know how to use standard POSIX libraries to make a call to some function that's part of a running daemon (background process).
For example, suppose that some code within process1 wants to make a call to a routine called "do_trap()" in another Daemon. How does one do this using the standard POSIX libraries, does anyone know?
Would I use signal.h functionality to accomplish this perhaps. If so, how? I've never done this before (in C).
Thank you kindly,
dedham_ma_man
Generally, daemons have two types of interfaces:
- Signals
- Pipes/Sockets
But you can also use named semaphores or other "global IPC" methods.
"do_trap()" sounds like a case for a signal, which on the user-side would look like this:
See for example:Code:... kill(pid, signo); ...
http://www.hmug.org/man/2/kill.php
--
Mats
Compilers can produce warnings - make the compiler programmers happy: Use them!
Please don't PM me for help - and no, I don't do help over instant messengers.
POSIX also supports message queues. They would probably not work as well for your app as some other IPC method, like named pipes or a socket, for example. Sockets are very commonly used by daemons that listen for requests and independently process them.
There's also RPC's:
http://www.opengroup.org/onlinepubs/9629399/chap2.htm
--
Mats
Compilers can produce warnings - make the compiler programmers happy: Use them!
Please don't PM me for help - and no, I don't do help over instant messengers.
Thank you all for the great responses - I learned a great deal from them.
I just found a good webpage that describes the basics of signaling, which is good for beginners to signaling like myself - http://www.cs.cf.ac.uk/Dave/C/node24...00000000000000
