newlib/winsup/cygwin/sync.h

56 lines
1.9 KiB
C++

/* sync.h: Header file for cygwin synchronization primitives.
Copyright 1999, 2000 Cygnus Solutions.
Written by Christopher Faylor <cgf@cygnus.com>
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
/* FIXME: Note that currently this class cannot be allocated via `new' since
there are issues with malloc and fork. */
class muto
{
LONG sync; /* Used to serialize access to this class. */
LONG visits; /* Count of number of times a thread has called acquire. */
LONG waiters; /* Number of threads waiting for lock. */
HANDLE bruteforce; /* event handle used to control waiting for lock. */
DWORD tid; /* Thread Id of lock owner. */
public:
class muto *next;
const char *name;
void *operator new (size_t, void *p) {return p;}
void *operator new (size_t) {return ::new muto; }
void operator delete (void *) {;} /* can't handle allocated mutos
currently */
/* This simple constructor is used for cases where no bruteforce
event handling is required. */
muto(): sync(0), visits(0), waiters(-1), bruteforce(0), tid(0), next (NULL) {;}
/* A more complicated constructor. */
muto(int inh, const char *name);
~muto ();
int acquire (DWORD ms = INFINITE); /* Acquire the lock. */
int release (); /* Release the lock. */
/* Return true if caller thread owns the lock. */
int ismine () {return tid == GetCurrentThreadId ();}
DWORD owner () {return tid;}
int unstable () {return !tid && (sync || waiters >= 0);}
};
extern muto muto_start;
/* Use a statically allocated buffer as the storage for a muto */
#define new_muto(__inh, __name) \
({ \
static __attribute__((section(".data_cygwin_nocopy"))) muto __mbuf; \
(void) new ((char *) &__mbuf) muto (__inh, __name); \
__mbuf.next = muto_start.next; \
muto_start.next = &__mbuf; \
&__mbuf; \
})