Create pthread c how to#

The user is not allowed to make any assumptions about this type. It's also available to any thread by calling pthread_self.

When creating a new thread, pthread_create stores it in a pointer to an opaque type pthread_t that the user passes. Pthreads takes the opaqueness of its types very seriously. pthreads doesn't care - all it needs is a pointer to a valid object, through which the object can be initialized, interacted with, or destroyed. He may choose to place them in static storage, allocate them dynamically, or even on stack for some uses.

Create pthread c how to#

The user knows best how to allocate the objects themselves.The API knows best how to allocate the contents of its objects - the user doesn't even have to know what those contents are.These functions take pointers to pthread types and don't actually allocate and deallocate the object themselves - only their contents. APIs have to be restrictive - otherwise their abstractions will leak, which is dangerous.Р”Р„ desired corollary of this design is consistent memory management: new pthread objects are initialized with pthread_init functions and cleaned up with pthread_destroy functions. Restrict what the user can do with your data and you won't get surprised by creative (ab)uses. Such opaqueness is great for encapsulation - an important concept in API design. A type such as pthread_mutex_t reveals nothing of its implementation, and you can't even look up its definition without digging deep in the sources of the library. The types provided by pthreads are completely opaque.