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pthreads
Aquarius_Girl
Aquarius_Girl

Reputation: 22946

What is the type of pthread_mutex_t?

From: https://www.sourceware.org/pthreads-win32/manual/pthread_mutex_init.html

Variables of type pthread_mutex_t can also be initialized statically,

So, what is the type of pthread_mutex_t?

Upvotes: 5

Views: 46584

Answers (3)

Scott 'scm6079'
Scott 'scm6079'

Reputation: 1567

From pthreadtypes.h, in my Linux distribution its definition is pretty clear as a typedef for a union, as defined below: 

/* Data structures for mutex handling.  The structure of the attribute
   type is not exposed on purpose.  */
typedef union
{
  struct __pthread_mutex_s
  {
    int __lock;
    unsigned int __count;
    int __owner;
    /* KIND must stay at this position in the structure to maintain
       binary compatibility.  */
    int __kind;
    unsigned int __nusers;
    __extension__ union
    {
      int __spins;
      __pthread_slist_t __list;
    };
  } __data;
  char __size[__SIZEOF_PTHREAD_MUTEX_T];
  long int __align;
} pthread_mutex_t;

You'll want to use it as their defined type, pthread_mutex_t of course -- since this type will vary by OS / distribution / etc.

Upvotes: 13

Matt
Matt

Reputation: 4049

pthread_mutex_t is a type, so it doesn't have a type itself. If you are curious about what this type is an alias for, on my machine I have:

struct _opaque_pthread_mutex_t {
  long __sig;
  char __opaque[__PTHREAD_MUTEX_SIZE__];
};

and then

typedef struct _opaque_pthread_mutex_t __darwin_pthread_mutex_t;

and finally:

typedef __darwin_pthread_mutex_t pthread_mutex_t;

Upvotes: 3

Carlos Martín Nieto
Carlos Martín Nieto

Reputation: 5277

That is the type. The implementation underneath is often a struct and you can look in the header files if you really care about the specific implementation of the library you're using, but those details don't matter for using it, you just care about the pthread_mutex_t type.

pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER;

Upvotes: 10

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