Hello everyone i have a question about timeouts in c so i ask you guys.
So i'm making a server application in C that uses POSIX threads to accept multiple simpultenious connections but implementing timeouts was harder than i expected as i read the message (HTTP requests) in parts first the start line than the headers etc, etc, and i initialy used select() to detect if the socket was ready for reading but that way if the client sends the start line only than the server will continue waiting for the headers and body without ever timing out so what i did is i put all the code that reads the message in one function and i wan't to implement a timeout for the entire function, say if the function doesnt return in x seconds than a timeout function is called and the thread is exited...
[Things that i have tried]
- putting multiple select calls (one for every socket read) but that ended up in a mess of having to calculate remaining time for each operation.
- i didn't actually try to use an alarm signal as i've heard that signals effect the entire process and not a specific thread that would cause one time out to timeout every parallel connection..
thanx in advance.. B)
There is no proper way to terminate a thread function other than letting it finish.
Every attempt to finish a thread from the outside could lead to resource (mostly but not only memory) leaks, state variables in nondeterministic state, and so. Please don't do it. Never. The normal way of terminating a thread function from the outside is to make it listen to some means of inter thread communication (which can be a sync object, a volatile variable or even a message loop), and exit the function core when it is necessary. Normally you would realize it by having a single test in the cycle condition of the thread if it is looping or testing before every long-running operation inside your thread.
Now if you store the timestamp of the function start and test at every cycle condition/long-running test if currenttimestamp > timestamp + timeout, you can exit from inside your thread and voilá; your problem is solved.