# README Synchronisation: Real POSIX API

In this homework, you'll use a real tool on Linux to find problems in
multi-threaded code. The tool is called **helgrind** (available as part of the
valgrind suite of debugging tools).

See <http://valgrind.org/docs/manual/hg-manual.html> for details about the tool,
including how to download and install it (if it's not already on your Linux
system).

You'll then look at a number of multi-threaded C programs to see how you can
use the tool to debug problematic threaded code.

Then, type **make** to build all the different programs. Examine the Makefile
for more details on how that works.

Then, you have a few different C programs to look at:

-   `main-race.c`:
    A simple race condition

-   `main-deadlock.c`:
    A simple deadlock

-   `main-deadlock-global.c`:
    A solution to the deadlock problem

-   `main-signal.c`:
    A simple child/parent signaling example

-   `main-signal-cv.c`:
    A more efficient signaling via condition variables

-   `mythreads.h`:
    Header file with wrappers to make code check errors and be more readable

With these programs, you can now answer the questions in the textbook.