Libc-498.1.5.tar.gz

[apple/libc.git] / include / libkern / OSMemoryNotification.h

diff --git a/include/libkern/OSMemoryNotification.h b/include/libkern/OSMemoryNotification.h
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+/*
+ * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#ifndef _OSMEMORYNOTIFICATION_H_
+#define _OSMEMORYNOTIFICATION_H_
+
+#include <sys/cdefs.h>
+
+/*
+**  OSMemoryNotification.h
+**  
+**  Kernel-generated notification mechanism to alert registered tasks when physical memory
+**  pressure reaches certain thresholds. Notifications are triggered in both directions
+**  so clients can manage their memory usage more and less aggressively.
+**
+*/
+
+__BEGIN_DECLS
+
+struct timeval;
+
+/*
+** Opaque type for notification object
+*/
+ 
+typedef struct _OSMemoryNotification * OSMemoryNotificationRef;
+
+/*
+** Threshold values for notifications
+*/
+ 
+typedef enum {
+       OSMemoryNotificationLevelAny      = -1,
+       OSMemoryNotificationLevelNormal   =  0,
+       OSMemoryNotificationLevelWarning  =  1,
+       OSMemoryNotificationLevelUrgent   =  2,
+       OSMemoryNotificationLevelCritical =  3
+} OSMemoryNotificationLevel;
+
+/*
+** Creation routines. Returns the created OSMemoryNotificationRef in the note param.
+** returns: 0 on success
+**          ENOMEM if insufficient memory or resources exists to create the notification object
+**          EINVAL if the threshold is not a valid notification level
+*/
+
+int OSMemoryNotificationCreate(OSMemoryNotificationRef *note);
+
+/*
+** returns: 0 on success
+**          EINVAL if the notification is not an initialized notification object
+*/
+
+int OSMemoryNotificationDestroy(OSMemoryNotificationRef note);
+
+/*
+** Block waiting for notification
+** returns: 0 on success, with the level that triggered the notification in the level param
+**          EINVAL if the notification object is invalid
+**          ETIMEDOUT if abstime passes before notification occurs
+*/
+int OSMemoryNotificationWait(OSMemoryNotificationRef note, OSMemoryNotificationLevel *level);
+int OSMemoryNotificationTimedWait(OSMemoryNotificationRef note, OSMemoryNotificationLevel *level, const struct timeval *abstime);
+
+/*
+** Simple polling interface to detect current memory pressure level
+*/
+
+OSMemoryNotificationLevel OSMemoryNotificationCurrentLevel(void);
+
+/*
+** External notify(3) string for manual notification setup
+*/
+
+extern const char *kOSMemoryNotificationName;
+
+__END_DECLS
+
+#endif /* _OSMEMORYNOTIFICATION_H_ */