xemu/include/qemu/thread-win32.h
Paolo Bonzini c7c4d063f5 qemu-thread: add QemuEvent
This emulates Win32 manual-reset events using futexes or conditional
variables.  Typical ways to use them are with multi-producer,
single-consumer data structures, to test for a complex condition whose
elements come from different threads:

    for (;;) {
        qemu_event_reset(ev);
        ... test complex condition ...
        if (condition is true) {
            break;
        }
        qemu_event_wait(ev);
    }

Or more efficiently (but with some duplication):

    ... evaluate condition ...
    while (!condition) {
        qemu_event_reset(ev);
        ... evaluate condition ...
        if (!condition) {
            qemu_event_wait(ev);
            ... evaluate condition ...
        }
    }

QemuEvent provides a very fast userspace path in the common case when
no other thread is waiting, or the event is not changing state.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-17 17:30:55 +02:00

34 lines
540 B
C

#ifndef __QEMU_THREAD_WIN32_H
#define __QEMU_THREAD_WIN32_H 1
#include "windows.h"
struct QemuMutex {
CRITICAL_SECTION lock;
LONG owner;
};
struct QemuCond {
LONG waiters, target;
HANDLE sema;
HANDLE continue_event;
};
struct QemuSemaphore {
HANDLE sema;
};
struct QemuEvent {
HANDLE event;
};
typedef struct QemuThreadData QemuThreadData;
struct QemuThread {
QemuThreadData *data;
unsigned tid;
};
/* Only valid for joinable threads. */
HANDLE qemu_thread_get_handle(QemuThread *thread);
#endif