libsync is a simple thread synchronization library for X86/X64 implemented in pure C. libsync has the pthread-like API and supports mutex, conditional variable and barrier currently.

futex is a complicated system call. Implementing my own synchronization library may help to understand it.

:::C
// static initialization
mutex_t mutex = MUTEX_INITIALIZER;
// dynamic initialization
mutex_init(&mutex);
// lock
mutex_lock(&mutex);
// unlock
mutex_unlock(&mutex);
// try lock
mutex_trylock(&mutex);
// destruct mutex
mutex_destroy(&mutex);
:::

libsync build successfully on my platform (gcc version 4.7.1 Linux Kernel 3.6.8 X86_64)

make clean && make

libsync provide two MACROS to tune the performance.

• SPIN is defined to make mutex_lock spin some times to acquire the lock instead of invoking futex_wait to sleep immediately.
• SPIN_TIMES is defined to make the user specify the spin times when SPIN is enabled;