Accessing global variables in pthreads in different c-files

Question

I have a main.c with a global variable called int countboards. In the main() I start a pthread, that listens to ONE TCP-Connection and runs that through (progs

Answer 1

You're seeing a cached copy in each thread. I would suggest declaring it volatile int countboards except that's really not a good way to go about things.

Globals are kinda evil. You'd be better served by passing a pointer to each thread and synchronizing with a mutex.

Edit: To expand on this since I was in a hurry last night ...

http://software.intel.com/en-us/blogs/2007/11/30/volatile-almost-useless-for-multi-threaded-programming/

As KasigiYabu mentions in the comments below, creating a "context" structure that contains all the information you want to share between the threads and passing that in to pthread_create as the last arg is a sound approach and is what I do as well in most cases.