GMutex

GMutex is a mutual exclusion primitive provided by GLib to synchronize access to shared data in multi-threaded programs. It is part of GLib's threading facilities and abstracts platform-specific synchronization primitives, such as pthread mutexes on POSIX systems and CRITICAL_SECTION on Windows, to offer a portable interface for locking critical sections.

A GMutex is created with g_mutex_new() and must be freed with g_mutex_free() when it is no longer needed. The typical pattern is to create a mutex once and reuse it to protect accesses to shared resources.

Core operations include g_mutex_lock, g_mutex_unlock, and g_mutex_trylock. The g_mutex_lock function blocks the calling thread until the mutex becomes available and then acquires the lock. The g_mutex_unlock function releases the lock. The g_mutex_trylock function attempts to acquire the lock without blocking and returns a gboolean indicating success; if the lock is not available, it returns FALSE.

GMutex is non-recursive by design; if the same thread attempts to lock it again while already holding the lock, a deadlock can occur. For scenarios requiring recursive locking, GLib provides a separate primitive called GRecMutex.

For static or global data, GLib also offers static mutex capabilities (such as GStaticMutex) to enable safe initialization without explicit dynamic allocation. GMutex is widely used within GLib and GTK code to protect data structures, global state, and other resources that must not be concurrently modified.

In summary, GMutex provides a portable, non-recursive mutex API for protecting critical sections, with a simple lifecycle and predictable blocking semantics suitable for cross-platform GLib-based applications.