互斥对象有所有权，不像信号量。尽管在互斥量范围内的任何线程都可以获得一个未锁定的互斥量，并锁定对同一关键代码段的访问，但只有锁定了互斥量的线程才应该解锁它。

The basic issue is concurrency. There is more than one flow of control. Think about two processes using a shared memory. Now only one process can access the shared memory at a time. If more than one process accesses the shared memory at a time, the contents of shared memory would get corrupted. It is like a railroad track. Only one train can run on it, else there would be an accident.So there is a signalling mechanism, which a driver checks. If the signal is green, the train can go and if it is red it has to wait to use the track. Similarly in case of shared memory, there is a binary semaphore. If the semaphore is 1, a process acquires it (makes it 0) and goes ahead and accesses it. If the semaphore is 0, the process waits. The functionality the binary semaphore has to provide is mutual exclusion (or mutex, in short) so that only one of the many concurrent entities (process or thread) mutually excludes others. It is a plus that we have counting semaphores, which help in synchronizing multiple instances of a resource.

互斥是信号量提供的基本功能。现在在线程上下文中，我们可能有不同的名称和语法。但基本概念是相同的:如何在并发编程中保持代码和数据的完整性。在我看来，像所有权和相关检查这样的东西是由实现提供的改进。

关于这个主题的好文章:

互斥量与信号量——第1部分:信号量 互斥量与信号量——第2部分:互斥量 互斥量与信号量——第3部分(最后一部分):互斥问题

来自第二部分:

The mutex is similar to the principles of the binary semaphore with one significant difference: the principle of ownership. Ownership is the simple concept that when a task locks (acquires) a mutex only it can unlock (release) it. If a task tries to unlock a mutex it hasn’t locked (thus doesn’t own) then an error condition is encountered and, most importantly, the mutex is not unlocked. If the mutual exclusion object doesn't have ownership then, irrelevant of what it is called, it is not a mutex.

正如这里许多人提到的，互斥锁用于保护关键代码段(又名临界段)。你将在同一个线程中获得互斥锁(lock)，进入临界区，释放互斥锁(unlock)。

在使用信号量时，您可以让一个线程(例如线程a)等待一个信号量，直到另一个线程(例如线程B)完成任何任务，然后为线程a设置信号量以停止等待，并继续其任务。

虽然二进制信号量可以用作互斥量，但互斥量是一个更具体的用例，因为只有锁定了互斥量的进程才应该解锁它。这种所有权限制使我们有可能对以下情况提供保护:

意外释放 递归死锁 任务死亡死锁

这些限制并不总是存在，因为它们降低了速度。在代码开发期间，您可以暂时启用这些检查。

例如，你可以在互斥锁中启用错误检查属性。错误检查互斥量返回EDEADLK，如果你试图锁定同一个互斥量两次，如果你解锁了一个不是你的互斥量，返回EPERM。

pthread_mutex_t mutex;
pthread_mutexattr_t attr;
pthread_mutexattr_init (&attr);
pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ERRORCHECK_NP);
pthread_mutex_init (&mutex, &attr);

一旦初始化，我们可以将这些检查放在我们的代码中，就像这样:

if(pthread_mutex_unlock(&mutex)==EPERM)
 printf("Unlock failed:Mutex not owned by this thread\n");

你可以通过以下方法清楚地记住不同之处:

互斥锁:用于保护关键区域， 互斥锁不能跨进程使用，只能在单个进程中使用 信号量:用于信号资源的可用性。 信号量既可以跨进程使用，也可以跨进程使用。